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Newton's second law for a particle is

Dynamics · FE Reference Handbook section

Dynamics
13 formulas
10 exam-style examples
~60 min
All Dynamics lectures

Handbook notes for this section

Definitions and conditions exactly as the handbook states them.

  • When motion exists only in a single dimension then, without loss of generality, it may be assumed to be in the x direction, and
  • If the force is constant (i.e., independent of time, displacement, and velocity) then

Core formulas for this FE topic

Definitions, applicability, units, assumptions and worked examples for each relation.

Worked exam-style examples

The four ways this section is written on the real exam — thoughts first, then equations, then substitution.

Example 1
Constant-acceleration kinematics — solve for final velocity — Newton's second law for a particle is

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 64.0000 ft/s; acceleration (a) = 8.5000 ft/s²; distance (s) = 208.0 ft, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=64.0000ft/sinitial velocity (v_{0}) = 64.0000 ft/s
  • acceleration(a)=8.5000ft/s2acceleration (a) = 8.5000 ft/s^{2}
  • distance(s)=208.0ftdistance (s) = 208.0 ft

Find

final velocity (v), in ft/s

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except v is given, so isolate v symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that v stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 64.0000 ft/s, acceleration (a) = 8.5000 ft/s², distance (s) = 208.0 ft.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    v=87.3613 ft/sv = 87.3613\ \text{ft/s}
  6. Step 6 — Check: returning v = 87.3613 ft/s to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
v=87.3613 ft/sv = 87.3613\ \text{ft/s}

Why the other options are there

  • 174.7 — kept a factor of two that cancels in the correct rearrangement.
  • 43.6807 — dropped that same factor in the other direction.
  • 96.0975 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 2
Constant-acceleration kinematics — solve for acceleration — Newton's second law for a particle is (2)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 68.0000 ft/s; distance (s) = 127.0 ft; final velocity (v) = 63.1000 ft/s, determine the acceleration (a) in ft/s².

Given

  • initialvelocity(v0)=68.0000ft/sinitial velocity (v_{0}) = 68.0000 ft/s
  • distance(s)=127.0ftdistance (s) = 127.0 ft
  • finalvelocity(v)=63.1000ft/sfinal velocity (v) = 63.1000 ft/s

Find

acceleration (a), in ft/s²

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except a is given, so isolate a symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that a stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 68.0000 ft/s, distance (s) = 127.0 ft, final velocity (v) = 63.1000 ft/s.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    a=−2.5291 ft/s²a = -2.5291\ \text{ft/s²}
  6. Step 6 — Check: returning a = -2.5291 ft/s² to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
a=−2.5291 ft/s²a = -2.5291\ \text{ft/s²}

Why the other options are there

  • -5.0582 — kept a factor of two that cancels in the correct rearrangement.
  • -1.2645 — dropped that same factor in the other direction.
  • -2.7820 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 3
Constant-acceleration kinematics — solve for distance — Newton's second law for a particle is (3)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 95.0000 ft/s; acceleration (a) = -13.0000 ft/s²; final velocity (v) = 78.0000 ft/s, determine the distance (s) in ft.

Given

  • initialvelocity(v0)=95.0000ft/sinitial velocity (v_{0}) = 95.0000 ft/s
  • acceleration(a)=−13.0000ft/s2acceleration (a) = -13.0000 ft/s^{2}
  • finalvelocity(v)=78.0000ft/sfinal velocity (v) = 78.0000 ft/s

Find

distance (s), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except s is given, so isolate s symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that s stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 95.0000 ft/s, acceleration (a) = -13.0000 ft/s², final velocity (v) = 78.0000 ft/s.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    s=113.1 fts = 113.1\ \text{ft}
  6. Step 6 — Check: returning s = 113.1 ft to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
s=113.1 fts = 113.1\ \text{ft}

Why the other options are there

  • 226.2 — kept a factor of two that cancels in the correct rearrangement.
  • 56.5577 — dropped that same factor in the other direction.
  • 124.4 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 4
Constant-acceleration kinematics — solve for final velocity (case 2) — Newton's second law for a particle is (4)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 38.0000 ft/s; acceleration (a) = -15.5000 ft/s²; distance (s) = 182.0 ft, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=38.0000ft/sinitial velocity (v_{0}) = 38.0000 ft/s
  • acceleration(a)=−15.5000ft/s2acceleration (a) = -15.5000 ft/s^{2}
  • distance(s)=182.0ftdistance (s) = 182.0 ft

Find

final velocity (v), in ft/s

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except v is given, so isolate v symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that v stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 38.0000 ft/s, acceleration (a) = -15.5000 ft/s², distance (s) = 182.0 ft.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    v=0.0000 ft/sv = 0.0000\ \text{ft/s}
  6. Step 6 — Check: returning v = 0.0000 ft/s to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
v=0.0000 ft/sv = 0.0000\ \text{ft/s}

Why the other options are there

  • 0.0000 — kept a factor of two that cancels in the correct rearrangement.
  • 0.0000 — dropped that same factor in the other direction.
  • 0.0000 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 5
Constant-acceleration kinematics — solve for acceleration (case 2) — Newton's second law for a particle is (5)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 20.0000 ft/s; distance (s) = 133.0 ft; final velocity (v) = 76.6000 ft/s, determine the acceleration (a) in ft/s².

Given

  • initialvelocity(v0)=20.0000ft/sinitial velocity (v_{0}) = 20.0000 ft/s
  • distance(s)=133.0ftdistance (s) = 133.0 ft
  • finalvelocity(v)=76.6000ft/sfinal velocity (v) = 76.6000 ft/s

Find

acceleration (a), in ft/s²

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except a is given, so isolate a symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that a stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 20.0000 ft/s, distance (s) = 133.0 ft, final velocity (v) = 76.6000 ft/s.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    a=20.5547 ft/s²a = 20.5547\ \text{ft/s²}
  6. Step 6 — Check: returning a = 20.5547 ft/s² to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
a=20.5547 ft/s²a = 20.5547\ \text{ft/s²}

Why the other options are there

  • 41.1095 — kept a factor of two that cancels in the correct rearrangement.
  • 10.2774 — dropped that same factor in the other direction.
  • 22.6102 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 6
Constant-acceleration kinematics — solve for distance (case 2) — Newton's second law for a particle is (6)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 26.0000 ft/s; acceleration (a) = 14.0000 ft/s²; final velocity (v) = 47.4000 ft/s, determine the distance (s) in ft.

Given

  • initialvelocity(v0)=26.0000ft/sinitial velocity (v_{0}) = 26.0000 ft/s
  • acceleration(a)=14.0000ft/s2acceleration (a) = 14.0000 ft/s^{2}
  • finalvelocity(v)=47.4000ft/sfinal velocity (v) = 47.4000 ft/s

Find

distance (s), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except s is given, so isolate s symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that s stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 26.0000 ft/s, acceleration (a) = 14.0000 ft/s², final velocity (v) = 47.4000 ft/s.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    s=56.0986 fts = 56.0986\ \text{ft}
  6. Step 6 — Check: returning s = 56.0986 ft to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
s=56.0986 fts = 56.0986\ \text{ft}

Why the other options are there

  • 112.2 — kept a factor of two that cancels in the correct rearrangement.
  • 28.0493 — dropped that same factor in the other direction.
  • 61.7084 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 7
Constant-acceleration kinematics — solve for final velocity (case 3) — Newton's second law for a particle is (7)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 40.0000 ft/s; acceleration (a) = 23.0000 ft/s²; distance (s) = 459.0 ft, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=40.0000ft/sinitial velocity (v_{0}) = 40.0000 ft/s
  • acceleration(a)=23.0000ft/s2acceleration (a) = 23.0000 ft/s^{2}
  • distance(s)=459.0ftdistance (s) = 459.0 ft

Find

final velocity (v), in ft/s

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except v is given, so isolate v symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that v stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 40.0000 ft/s, acceleration (a) = 23.0000 ft/s², distance (s) = 459.0 ft.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    v=150.7 ft/sv = 150.7\ \text{ft/s}
  6. Step 6 — Check: returning v = 150.7 ft/s to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
v=150.7 ft/sv = 150.7\ \text{ft/s}

Why the other options are there

  • 301.4 — kept a factor of two that cancels in the correct rearrangement.
  • 75.3558 — dropped that same factor in the other direction.
  • 165.8 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 8
Constant-acceleration kinematics — solve for acceleration (case 3) — Newton's second law for a particle is (8)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 59.0000 ft/s; distance (s) = 418.0 ft; final velocity (v) = 145.1 ft/s, determine the acceleration (a) in ft/s².

Given

  • initialvelocity(v0)=59.0000ft/sinitial velocity (v_{0}) = 59.0000 ft/s
  • distance(s)=418.0ftdistance (s) = 418.0 ft
  • finalvelocity(v)=145.1ft/sfinal velocity (v) = 145.1 ft/s

Find

acceleration (a), in ft/s²

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except a is given, so isolate a symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that a stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 59.0000 ft/s, distance (s) = 418.0 ft, final velocity (v) = 145.1 ft/s.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    a=21.0203 ft/s²a = 21.0203\ \text{ft/s²}
  6. Step 6 — Check: returning a = 21.0203 ft/s² to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
a=21.0203 ft/s²a = 21.0203\ \text{ft/s²}

Why the other options are there

  • 42.0407 — kept a factor of two that cancels in the correct rearrangement.
  • 10.5102 — dropped that same factor in the other direction.
  • 23.1224 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 9
Constant-acceleration kinematics — solve for distance (case 3) — Newton's second law for a particle is (9)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 95.0000 ft/s; acceleration (a) = -9.0000 ft/s²; final velocity (v) = 23.7000 ft/s, determine the distance (s) in ft.

Given

  • initialvelocity(v0)=95.0000ft/sinitial velocity (v_{0}) = 95.0000 ft/s
  • acceleration(a)=−9.0000ft/s2acceleration (a) = -9.0000 ft/s^{2}
  • finalvelocity(v)=23.7000ft/sfinal velocity (v) = 23.7000 ft/s

Find

distance (s), in ft

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except s is given, so isolate s symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that s stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 95.0000 ft/s, acceleration (a) = -9.0000 ft/s², final velocity (v) = 23.7000 ft/s.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    s=470.2 fts = 470.2\ \text{ft}
  6. Step 6 — Check: returning s = 470.2 ft to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
s=470.2 fts = 470.2\ \text{ft}

Why the other options are there

  • 940.4 — kept a factor of two that cancels in the correct rearrangement.
  • 235.1 — dropped that same factor in the other direction.
  • 517.2 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

Example 10
Constant-acceleration kinematics — solve for final velocity (case 4) — Newton's second law for a particle is (10)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 54.0000 ft/s; acceleration (a) = -4.0000 ft/s²; distance (s) = 440.0 ft, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=54.0000ft/sinitial velocity (v_{0}) = 54.0000 ft/s
  • acceleration(a)=−4.0000ft/s2acceleration (a) = -4.0000 ft/s^{2}
  • distance(s)=440.0ftdistance (s) = 440.0 ft

Find

final velocity (v), in ft/s

Start with the thinking

  • The governing relation printed in this handbook section is Constant-acceleration kinematics.
  • Everything except v is given, so isolate v symbolically first — never rearrange after the numbers are in.
  • Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
  • Dynamics items reward recognising the unknown before touching a calculator.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v2=v02+2asv^2 = v_0^2 + 2 a s
  2. Step 2 — Rearrange the relation so that v stands alone on the left-hand side.

  3. Step 3 — List the givens: initial velocity (v0) = 54.0000 ft/s, acceleration (a) = -4.0000 ft/s², distance (s) = 440.0 ft.

  4. Step 4 — Substitute the given values into the rearranged relation.

  5. Step 5 — Evaluate:

    v=0.0000 ft/sv = 0.0000\ \text{ft/s}
  6. Step 6 — Check: returning v = 0.0000 ft/s to

    v2=v02+2asv^2 = v_0^2 + 2 a s

    reproduces the given quantities, and both sides carry the same units.

Answer:
v=0.0000 ft/sv = 0.0000\ \text{ft/s}

Why the other options are there

  • 0.0000 — kept a factor of two that cancels in the correct rearrangement.
  • 0.0000 — dropped that same factor in the other direction.
  • 0.0000 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Newton's second law for a particle is

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