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Worksheet: Forces and Newton's Second Law of Motion

Q1:

A sports car of mass 1 5 0 0 kg accelerates from 0 m/s to 30 m/s in a time of 10 s. What average force is exerted on the car during this acceleration?

  • A 4 . 1 × 1 0 3 N
  • B 3 . 8 × 1 0 3 N
  • C 5 . 0 × 1 0 3 N
  • D 4 . 5 × 1 0 3 N
  • E 5 . 4 × 1 0 3 N

Q2:

A car with a mass of 1 0 0 0 kg applies brakes when it is moving at 90.0 km/h, and the car comes to rest after travelling 40.0 m. What is the net force on the car during its deceleration?

Q3:

Find the magnitude of the net force required to bring a car to rest if the mass of the car is 1 0 5 0 kg, its initial speed is 40.0 km/h, and its stopping distance is 25.0 m.

Q4:

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?

Q5:

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?

Q6:

The rocket sled shown in the accompanying diagram has a mass of 2 . 1 0 × 1 0 3 kg. The sled decelerates at a rate of 196 m/s2. What force is necessary to produce this deceleration? Assume that the rockets have finished firing when the deceleration begins.

Q7:

A particle that is initially at rest is acted upon by a single force F i 1 = 1 8 N for a time interval of 5.0 s.

What is the particle’s acceleration?

  • A 3 6 i m/s2
  • B 1 8 i m/s2
  • C 1 . 8 i m/s2
  • D 9 . 0 i m/s2
  • E 9 0 i m/s2

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

Q8:

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.

Q9:

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?

Q10:

What force does a trampoline have to apply to a 48.6-kg gymnast, to accelerate her vertically upward at 6.43 m/s2?

Q11:

A sprinter with a mass of 57.0 kg accelerates at 3.922 m/s2. 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 5 . 0 0 j m/s at the instant 𝑡 = 0 . 0 0 s . The helicopter is uniformly accelerated for 2.00 s. At the end of that interval, it has a velocity of ( 6 . 0 0 + 1 2 . 0 0 ) i j m/s.

What magnitude average force acted on the helicopter between 𝑡 = 0 . 0 0 s and 𝑡 = 2 . 0 0 s ?

At what counterclockwise angle from the positive 𝑥 -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/s2?

Q15:

Find the mass of a car that is given an acceleration of 0 . 2 j m/s2 by a force of 6 0 0 j N.

Q16:

A particle of mass 4.0 kg is acted upon by four forces of magnitudes 𝐹 = 1 0 . 0 1 N , 𝐹 = 4 0 . 0 2 N , 𝐹 = 5 . 0 3 N , and 𝐹 = 2 . 0 4 N . 𝐹 1 acts at an angle of 3 0 above the positive 𝑥 -direction, 𝐹 2 acts in the negative 𝑦 -direction, 𝐹 3 acts in the negative 𝑥 -direction, and 𝐹 4 acts in the positive 𝑦 -direction.

What is the particle’s acceleration vector?

  • A ( 1 . 1 1 4 ) i j m/s2
  • B 7 . 3 j m/s2
  • C ( 3 . 7 3 3 ) i j m/s2
  • D ( 0 . 9 2 8 . 3 ) i j m/s2
  • E ( 2 . 9 3 8 ) i j m/s2

What is the magnitude of the particle’s acceleration?

At what angle below the positive 𝑥 -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 a i j = ( 3 . 0 0 + 7 . 0 0 ) / m s 2 .

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

  • A ( 1 . 2 0 2 . 8 0 ) i j N
  • B ( 7 . 5 0 + 1 7 . 5 ) i j N
  • C ( 2 . 8 0 + 1 . 2 0 ) i j N
  • D ( 1 . 2 0 + 2 . 8 0 ) i j N
  • E ( 1 7 . 5 7 . 5 0 ) i j 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 6 × 1 0 7 kg. What acceleration of the ship is produced by applying to it a force of 6 MN?