Newton's second law for a particle is
Dynamics · FE Reference Handbook section
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.
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that v stands alone on the left-hand side.
Step 3 — List the givens: initial velocity (v0) = 64.0000 ft/s, acceleration (a) = 8.5000 ft/s², distance (s) = 208.0 ft.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning v = 87.3613 ft/s to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that a stands alone on the left-hand side.
Step 3 — List the givens: initial velocity (v0) = 68.0000 ft/s, distance (s) = 127.0 ft, final velocity (v) = 63.1000 ft/s.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning a = -2.5291 ft/s² to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that s stands alone on the left-hand side.
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.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning s = 113.1 ft to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that v stands alone on the left-hand side.
Step 3 — List the givens: initial velocity (v0) = 38.0000 ft/s, acceleration (a) = -15.5000 ft/s², distance (s) = 182.0 ft.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning v = 0.0000 ft/s to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that a stands alone on the left-hand side.
Step 3 — List the givens: initial velocity (v0) = 20.0000 ft/s, distance (s) = 133.0 ft, final velocity (v) = 76.6000 ft/s.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning a = 20.5547 ft/s² to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that s stands alone on the left-hand side.
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.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning s = 56.0986 ft to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that v stands alone on the left-hand side.
Step 3 — List the givens: initial velocity (v0) = 40.0000 ft/s, acceleration (a) = 23.0000 ft/s², distance (s) = 459.0 ft.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning v = 150.7 ft/s to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that a stands alone on the left-hand side.
Step 3 — List the givens: initial velocity (v0) = 59.0000 ft/s, distance (s) = 418.0 ft, final velocity (v) = 145.1 ft/s.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning a = 21.0203 ft/s² to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that s stands alone on the left-hand side.
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.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning s = 470.2 ft to
reproduces the given quantities, and both sides carry the same units.
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
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
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
Step 1 — State the governing relation:
Step 2 — Rearrange the relation so that v stands alone on the left-hand side.
Step 3 — List the givens: initial velocity (v0) = 54.0000 ft/s, acceleration (a) = -4.0000 ft/s², distance (s) = 440.0 ft.
Step 4 — Substitute the given values into the rearranged relation.
Step 5 — Evaluate:
Step 6 — Check: returning v = 0.0000 ft/s to
reproduces the given quantities, and both sides carry the same units.
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