In this worksheet, we will practice identifying Newton's second law of motion as the relationship between an object's mass and its resultant acceleration when a force is applied to it.

**Q3: **

Find the magnitude of the net force required to bring a car to rest if the mass of the car is kg, its initial speed is 40.0 km/h, and its stopping distance is 25.0 m.

**Q4: **

A cart with a mass of 18 kg is at rest on a level floor. A constant 15-N force is applied to the cart at an angle below the horizontal. If friction is negligible, what is the speed of the cart when the force is applied over a distance 6.7 m?

**Q5: **

A baseball catcher is performing a stunt for a television commercial. He will catch a baseball (mass 145 g) dropped from a height of 60.0 m above his glove. His glove stops the ball in 0.0100 s. What is the force exerted by his glove on the ball?

**Q6: **

A baby dolphin of mass 35.0 kg decelerates from a horizontal speed of 12.0 m/s to a horizontal speed of 7.50 m/s, taking 2.30 s. What average force is exerted to slow the dolphin?

**Q7: **

The rocket sled shown in the accompanying diagram has a mass of
kg.
The sled decelerates at a rate of 196 m/s^{2}.
What force is necessary to produce this deceleration?
Assume that the rockets have finished firing when the deceleration begins.

**Q8: **

A particle that is initially at rest is acted upon by a single force for a time interval of 5.0 s.

What is the particle’s acceleration?

- A
m/s
^{2} - B
m/s
^{2} - C
m/s
^{2} - D
m/s
^{2} - E
m/s
^{2}

What is the magnitude of the displacement of the particle at the end of the interval during which it is accelerated?

**Q9: **

A cleaner pushes a laundry cart of mass 6.30 kg. The cleaner pushes with a net external force of 53.4 N. Calculate the magnitude of the cart’s acceleration.

**Q10: **

What force does a trampoline have to apply to a 48.6-kg gymnast,
to accelerate her vertically upward at
6.43 m/s^{2}?

**Q11: **

A sprinter with a mass of 57.0 kg
accelerates at 3.922 m/s^{2}.
What is the magnitude of the net external force on her?

**Q12: **

What is Newton’s second law of motion also known as?

- Athe law of action-reaction
- Bthe law of inertia
- Cthe law of gravitational attraction
- Dthe law of force
- Ethe law of conservation of energy

**Q13: **

A model helicopter of mass 1.50 kg has a velocity m/s at the instant . The helicopter is uniformly accelerated for 2.00 s. At the end of that interval, it has a velocity of m/s.

What magnitude average force acted on the helicopter between and ?

At what counterclockwise angle from the positive -direction was the force on the helicopter applied?

**Q14: **

A farmer is lifting some moderately heavy rocks from a field to plant crops.
He lifts a stone that weighs
180 N. What magnitude
force does the farmer apply if the stone accelerates at a rate of
1.50 m/s^{2}?

**Q15: **

Find the mass of a car that is given an
acceleration of m/s^{2}
by a force of N.

**Q16: **

A particle of mass 4.0 kg is acted upon by four forces of magnitudes , , , and . acts at an angle of above the positive -direction, acts in the negative -direction, acts in the negative -direction, and acts in the positive -direction.

What is the particle’s acceleration vector?

- A
m/s
^{2} - B
m/s
^{2} - C
m/s
^{2} - D
m/s
^{2} - E
m/s
^{2}

What is the magnitude of the particle’s acceleration?

At what angle below the positive -direction is the particle’s acceleration directed?

**Q17: **

A soccer ball of mass 0.400 kg is kicked across a field by a player and is given the acceleration .

State the force vector for the applied force on the ball.

- A N
- B N
- C N
- D N
- E N

What magnitude force was applied to the ball?

At what angle above the horizontal was the force applied?

**Q18: **

A cruise ship has a mass of kg. What acceleration of the ship is produced by applying to it a force of 6 MN?