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Constant Acceleration

Dynamics · FE Reference Handbook section

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

Handbook notes for this section

Definitions and conditions exactly as the handbook states them.

  • The equations for the velocity and displacement when acceleration is a constant are given as
  • An additional equation for velocity as a function of position may be written as
  • For constant angular acceleration, the equations for angular velocity and displacement are
  • An additional equation for angular velocity as a function of angular position may be written as

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 — Constant Acceleration

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 83.0000 ft/s; acceleration (a) = -1.5000 ft/s²; distance (s) = 426.0 ft, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=83.0000ft/sinitial velocity (v_{0}) = 83.0000 ft/s
  • acceleration(a)=−1.5000ft/s2acceleration (a) = -1.5000 ft/s^{2}
  • distance(s)=426.0ftdistance (s) = 426.0 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) = 83.0000 ft/s, acceleration (a) = -1.5000 ft/s², distance (s) = 426.0 ft.

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

  5. Step 5 — Evaluate:

    v=74.9066 ft/sv = 74.9066\ \text{ft/s}
  6. Step 6 — Check: returning v = 74.9066 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=74.9066 ft/sv = 74.9066\ \text{ft/s}

Why the other options are there

  • 149.8 — kept a factor of two that cancels in the correct rearrangement.
  • 37.4533 — dropped that same factor in the other direction.
  • 82.3973 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Constant Acceleration

Example 2
Constant acceleration — solve for final velocity — Constant Acceleration (2)

An elevator speeds up with constant acceleration before reaching cruise speed. Given initial velocity (v_0) = 43.5000 ft/s; constant acceleration (a) = 13.9000 ft/s^2; time (t) = 9.9000 s, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=43.5000ft/sinitial velocity (v_0) = 43.5000 ft/s
  • constantacceleration(a)=13.9000ft/s2constant acceleration (a) = 13.9000 ft/s^2
  • time(t)=9.9000stime (t) = 9.9000 s

Find

final velocity (v), in ft/s

Start with the thinking

  • The governing relation printed in this handbook section is Constant acceleration.
  • 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.
  • Constant acceleration kinematics relates initial velocity, final velocity, acceleration, and time for a particle.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v=v0+atv = v_0 + a t
  2. Step 2 — Rearrange symbolically for v:

    v=v0+atv = v_0 + a t
  3. Step 3 — List the givens: initial velocity (v_0) = 43.5000 ft/s, constant acceleration (a) = 13.9000 ft/s^2, time (t) = 9.9000 s.

  4. Step 4 — Substitute the given values:

    v=v0+13.90009.9000v = v_0 + 13.9000 9.9000
  5. Step 5 — Evaluate:

    v=181.1 ft/sv = 181.1\ \text{ft/s}
  6. Step 6 — Check: returning v = 181.1 ft/s to

    v=v0+atv = v_0 + a t

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

Answer:
v=181.1 ft/sv = 181.1\ \text{ft/s}

Why the other options are there

  • 362.2 — kept a factor of two that cancels in the correct rearrangement.
  • 90.5550 — dropped that same factor in the other direction.
  • 199.2 — rounded an intermediate value before the final step.

Reference: FE Handbook — Dynamics: Constant Acceleration

Example 3
Constant-acceleration kinematics — solve for acceleration — Constant Acceleration (3)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 45.0000 ft/s; distance (s) = 58.0000 ft; final velocity (v) = 112.5 ft/s, determine the acceleration (a) in ft/s².

Given

  • initialvelocity(v0)=45.0000ft/sinitial velocity (v_{0}) = 45.0000 ft/s
  • distance(s)=58.0000ftdistance (s) = 58.0000 ft
  • finalvelocity(v)=112.5ft/sfinal velocity (v) = 112.5 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) = 45.0000 ft/s, distance (s) = 58.0000 ft, final velocity (v) = 112.5 ft/s.

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

  5. Step 5 — Evaluate:

    a=91.6487 ft/s²a = 91.6487\ \text{ft/s²}
  6. Step 6 — Check: returning a = 91.6487 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=91.6487 ft/s²a = 91.6487\ \text{ft/s²}

Why the other options are there

  • 183.3 — kept a factor of two that cancels in the correct rearrangement.
  • 45.8244 — dropped that same factor in the other direction.
  • 100.8 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Constant Acceleration

Example 4
Constant acceleration — solve for initial velocity — Constant Acceleration (4)

A dropped object near Earth's surface undergoes constant acceleration due to gravity. Given constant acceleration (a) = 31.7000 ft/s^2; time (t) = 4.2000 s; final velocity (v) = 143.3 ft/s, determine the initial velocity (v_0) in ft/s.

Given

  • constantacceleration(a)=31.7000ft/s2constant acceleration (a) = 31.7000 ft/s^2
  • time(t)=4.2000stime (t) = 4.2000 s
  • finalvelocity(v)=143.3ft/sfinal velocity (v) = 143.3 ft/s

Find

initial velocity (v_0), in ft/s

Start with the thinking

  • The governing relation printed in this handbook section is Constant acceleration.
  • Everything except v_0 is given, so isolate v_0 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.
  • Constant acceleration kinematics relates initial velocity, final velocity, acceleration, and time for a particle.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v=v0+atv = v_0 + a t
  2. Step 2 — Rearrange symbolically for v_0:

    v0=v−atv_{0} = v - a t
  3. Step 3 — List the givens: constant acceleration (a) = 31.7000 ft/s^2, time (t) = 4.2000 s, final velocity (v) = 143.3 ft/s.

  4. Step 4 — Substitute the given values:

    v0=143.3−31.70004.2000v_{0} = 143.3 - 31.7000 4.2000
  5. Step 5 — Evaluate:

    v0=10.1600 ft/sv_{0} = 10.1600\ \text{ft/s}
  6. Step 6 — Check: returning v_0 = 10.1600 ft/s to

    v=v0+atv = v_0 + a t

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

Answer:
v0=10.1600 ft/sv_{0} = 10.1600\ \text{ft/s}

Why the other options are there

  • 20.3200 — kept a factor of two that cancels in the correct rearrangement.
  • 5.0800 — dropped that same factor in the other direction.
  • 11.1760 — rounded an intermediate value before the final step.

Reference: FE Handbook — Dynamics: Constant Acceleration

Example 5
Constant-acceleration kinematics — solve for distance — Constant Acceleration (5)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 93.0000 ft/s; acceleration (a) = -14.5000 ft/s²; final velocity (v) = 81.0000 ft/s, determine the distance (s) in ft.

Given

  • initialvelocity(v0)=93.0000ft/sinitial velocity (v_{0}) = 93.0000 ft/s
  • acceleration(a)=−14.5000ft/s2acceleration (a) = -14.5000 ft/s^{2}
  • finalvelocity(v)=81.0000ft/sfinal velocity (v) = 81.0000 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) = 93.0000 ft/s, acceleration (a) = -14.5000 ft/s², final velocity (v) = 81.0000 ft/s.

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

  5. Step 5 — Evaluate:

    s=72.0000 fts = 72.0000\ \text{ft}
  6. Step 6 — Check: returning s = 72.0000 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=72.0000 fts = 72.0000\ \text{ft}

Why the other options are there

  • 144.0 — kept a factor of two that cancels in the correct rearrangement.
  • 36.0000 — dropped that same factor in the other direction.
  • 79.2000 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Constant Acceleration

Example 6
Constant acceleration — solve for constant acceleration — Constant Acceleration (6)

A car accelerates from a stoplight under constant acceleration. Given initial velocity (v_0) = 32.5000 ft/s; time (t) = 6.0000 s; final velocity (v) = 193.2 ft/s, determine the constant acceleration (a) in ft/s^2.

Given

  • initialvelocity(v0)=32.5000ft/sinitial velocity (v_0) = 32.5000 ft/s
  • time(t)=6.0000stime (t) = 6.0000 s
  • finalvelocity(v)=193.2ft/sfinal velocity (v) = 193.2 ft/s

Find

constant acceleration (a), in ft/s^2

Start with the thinking

  • The governing relation printed in this handbook section is Constant acceleration.
  • 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.
  • Constant acceleration kinematics relates initial velocity, final velocity, acceleration, and time for a particle.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v=v0+atv = v_0 + a t
  2. Step 2 — Rearrange symbolically for a:

    a=v−v0ta = \dfrac{v - v_0}{t}
  3. Step 3 — List the givens: initial velocity (v_0) = 32.5000 ft/s, time (t) = 6.0000 s, final velocity (v) = 193.2 ft/s.

  4. Step 4 — Substitute the given values:

    a=193.2−v06.0000a = \dfrac{193.2 - v_0}{6.0000}
  5. Step 5 — Evaluate:

    a = 26.7833\ \text{ft/s^2}
  6. Step 6 — Check: returning a = 26.7833 ft/s^2 to

    v=v0+atv = v_0 + a t

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

Answer:
a = 26.7833\ \text{ft/s^2}

Why the other options are there

  • 53.5667 — kept a factor of two that cancels in the correct rearrangement.
  • 13.3917 — dropped that same factor in the other direction.
  • 29.4617 — rounded an intermediate value before the final step.

Reference: FE Handbook — Dynamics: Constant Acceleration

Example 7
Constant-acceleration kinematics — solve for final velocity (case 2) — Constant Acceleration (7)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 23.0000 ft/s; acceleration (a) = 27.0000 ft/s²; distance (s) = 372.0 ft, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=23.0000ft/sinitial velocity (v_{0}) = 23.0000 ft/s
  • acceleration(a)=27.0000ft/s2acceleration (a) = 27.0000 ft/s^{2}
  • distance(s)=372.0ftdistance (s) = 372.0 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) = 23.0000 ft/s, acceleration (a) = 27.0000 ft/s², distance (s) = 372.0 ft.

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

  5. Step 5 — Evaluate:

    v=143.6 ft/sv = 143.6\ \text{ft/s}
  6. Step 6 — Check: returning v = 143.6 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=143.6 ft/sv = 143.6\ \text{ft/s}

Why the other options are there

  • 287.2 — kept a factor of two that cancels in the correct rearrangement.
  • 71.7931 — dropped that same factor in the other direction.
  • 157.9 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Constant Acceleration

Example 8
Constant acceleration — solve for time — Constant Acceleration (8)

An elevator speeds up with constant acceleration before reaching cruise speed. Given initial velocity (v_0) = 51.5000 ft/s; constant acceleration (a) = 19.2000 ft/s^2; final velocity (v) = 369.9 ft/s, determine the time (t) in s.

Given

  • initialvelocity(v0)=51.5000ft/sinitial velocity (v_0) = 51.5000 ft/s
  • constantacceleration(a)=19.2000ft/s2constant acceleration (a) = 19.2000 ft/s^2
  • finalvelocity(v)=369.9ft/sfinal velocity (v) = 369.9 ft/s

Find

time (t), in s

Start with the thinking

  • The governing relation printed in this handbook section is Constant acceleration.
  • Everything except t is given, so isolate t 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.
  • Constant acceleration kinematics relates initial velocity, final velocity, acceleration, and time for a particle.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v=v0+atv = v_0 + a t
  2. Step 2 — Rearrange symbolically for t:

    t=v−v0at = \dfrac{v - v_0}{a}
  3. Step 3 — List the givens: initial velocity (v_0) = 51.5000 ft/s, constant acceleration (a) = 19.2000 ft/s^2, final velocity (v) = 369.9 ft/s.

  4. Step 4 — Substitute the given values:

    t=369.9−v019.2000t = \dfrac{369.9 - v_0}{19.2000}
  5. Step 5 — Evaluate:

    t=16.5833 st = 16.5833\ \text{s}
  6. Step 6 — Check: returning t = 16.5833 s to

    v=v0+atv = v_0 + a t

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

Answer:
t=16.5833 st = 16.5833\ \text{s}

Why the other options are there

  • 33.1667 — kept a factor of two that cancels in the correct rearrangement.
  • 8.2917 — dropped that same factor in the other direction.
  • 18.2417 — rounded an intermediate value before the final step.

Reference: FE Handbook — Dynamics: Constant Acceleration

Example 9
Constant-acceleration kinematics — solve for acceleration (case 2) — Constant Acceleration (9)

A dynamics problem uses Constant-acceleration kinematics. Given initial velocity (v0) = 78.0000 ft/s; distance (s) = 367.0 ft; final velocity (v) = 9.0000 ft/s, determine the acceleration (a) in ft/s².

Given

  • initialvelocity(v0)=78.0000ft/sinitial velocity (v_{0}) = 78.0000 ft/s
  • distance(s)=367.0ftdistance (s) = 367.0 ft
  • finalvelocity(v)=9.0000ft/sfinal velocity (v) = 9.0000 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) = 78.0000 ft/s, distance (s) = 367.0 ft, final velocity (v) = 9.0000 ft/s.

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

  5. Step 5 — Evaluate:

    a=−8.1785 ft/s²a = -8.1785\ \text{ft/s²}
  6. Step 6 — Check: returning a = -8.1785 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=−8.1785 ft/s²a = -8.1785\ \text{ft/s²}

Why the other options are there

  • -16.3569 — kept a factor of two that cancels in the correct rearrangement.
  • -4.0892 — dropped that same factor in the other direction.
  • -8.9963 — rounded an intermediate value before the final step.

Reference: FE Reference Handbook — Dynamics → Constant Acceleration

Example 10
Constant acceleration — solve for final velocity (case 2) — Constant Acceleration (10)

A dropped object near Earth's surface undergoes constant acceleration due to gravity. Given initial velocity (v_0) = 35.5000 ft/s; constant acceleration (a) = 7.0000 ft/s^2; time (t) = 1.9000 s, determine the final velocity (v) in ft/s.

Given

  • initialvelocity(v0)=35.5000ft/sinitial velocity (v_0) = 35.5000 ft/s
  • constantacceleration(a)=7.0000ft/s2constant acceleration (a) = 7.0000 ft/s^2
  • time(t)=1.9000stime (t) = 1.9000 s

Find

final velocity (v), in ft/s

Start with the thinking

  • The governing relation printed in this handbook section is Constant acceleration.
  • 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.
  • Constant acceleration kinematics relates initial velocity, final velocity, acceleration, and time for a particle.

Step-by-step solution

  1. Step 1 — State the governing relation:

    v=v0+atv = v_0 + a t
  2. Step 2 — Rearrange symbolically for v:

    v=v0+atv = v_0 + a t
  3. Step 3 — List the givens: initial velocity (v_0) = 35.5000 ft/s, constant acceleration (a) = 7.0000 ft/s^2, time (t) = 1.9000 s.

  4. Step 4 — Substitute the given values:

    v=v0+7.00001.9000v = v_0 + 7.0000 1.9000
  5. Step 5 — Evaluate:

    v=48.8000 ft/sv = 48.8000\ \text{ft/s}
  6. Step 6 — Check: returning v = 48.8000 ft/s to

    v=v0+atv = v_0 + a t

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

Answer:
v=48.8000 ft/sv = 48.8000\ \text{ft/s}

Why the other options are there

  • 97.6000 — kept a factor of two that cancels in the correct rearrangement.
  • 24.4000 — dropped that same factor in the other direction.
  • 53.6800 — rounded an intermediate value before the final step.

Reference: FE Handbook — Dynamics: Constant Acceleration

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