SmarterEd

Aussie Maths & Science Teachers: Save your time with SmarterEd

PHYSICS, M2 EQ-Bank 3 MC

Two balls are dropped vertically from a cliff. Ball is dropped first. One second later, Ball , which has half the mass of Ball , is also dropped from the same height. Assume air resistance is negligible and both balls are dropped from rest.

Which of the following is correct?

  1. Ball will hit the ground with twice the speed of Ball .
  2. Ball will accelerate slower because it has less mass.
  3. The balls will strike the ground more than one second apart.
  4. The distance between the balls increases while they are falling.
Show Answers Only

Show Worked Solution

→ Both balls will experience the same acceleration as they are both being acted on by gravity .

→ The distance the balls fall during flight is given by  .

→ When 

Distance travelled by Ball

Distance travelled by Ball (distance between balls = 4.9 m)

→ When 

Distance travelled by Ball  

Distance travelled by Ball (distance between the balls = 14.7 m)

→ Due to the factor of in the distance equation, the distance between the balls will increase while they are falling.

PHYSICS, M2 EQ-Bank 2

A block is being dragged along a flat surface with a horizontal force of 30 being applied to it.

The mass of the block is 6 kilograms.

If the block is travelling at a constant velocity, determine the magnitude of the frictional forces acting on the block, giving reasons for your answer.   (2 marks)

Show Answers Only

→ As the block is travelling at a constant velocity, the sum of all the forces acting on the block must add to 0. 

→ The frictional forces must be equal in magnitude and opposite to the applied force.

→ Therefore, the magnitude of the frictional forces is 30 .

Show Worked Solution

→ As the block is travelling at a constant velocity, the sum of all the forces acting on the block must add to 0. 

→ The frictional forces must be equal in magnitude and opposite to the applied force.

→ Therefore, the magnitude of the frictional forces is 30 .

PHYSICS, M2 2020 VCE 9-10 MC

Two blocks of mass 5 kg and 10 kg are placed in contact on a frictionless horizontal surface, as shown in the diagram below. A constant horizontal force, , is applied to the 5 kg block.
 
 


 

Which one of the following statements is correct?

  1. The net force on each block is the same.
  2. The acceleration experienced by the 5 kg block is twice the acceleration experienced by the 10 kg block.
  3. The magnitude of the net force on the 5 kg block is half the magnitude of the net force on the 10 kg block.
  4. The magnitude of the net force on the 5 kg block is twice the magnitude of the net force on the 10 kg block.

 

If the force has a magnitude of 250 N, what is the work done by the force in moving the blocks in a straight line for a distance of 20 m?

Show Answers Only

Show Worked Solution

Using Newton’s second Law:  .

→ The blocks will experience the same acceleration.

→ Both blocks will have the same force to mass ratio. Since the 5 kg block is half the mass of the 10 kg block, it will experience half the magnitude of the net force as the 10 kg block.

♦ Mean mark 49%.

 

 
   
   
   

 

PHYSICS, M2 2022 VCE 9 MC

Two students pull on opposite ends of a rope, as shown in the diagram below. Each student pulls with a force of 400 N.
 

Which one of the following is closest to the magnitude of the force of the rope on each student?

Show Answers Only

Show Worked Solution

→ Newton’s 3rd Law states that every action has an equal and opposite reaction.

→ As each student exerts a force of 400 N on the rope, the rope will exert a force of 400 N on the student.

♦ Mean mark 52%.

PHYSICS, M2 2012 HSC 11 MC

Which of the following is correct about the forces acting during a rocket launch?

  1. Equal and opposite forces act on the rocket. This enables it to continue to accelerate even in the vacuum of space.
  2. The engines exert an upward thrust on the rocket. This thrust exceeds the downward force of the engines on the air.
  3. The rocket engines exert a downward force on the gases being expelled. These gases exert an upward force on the engines.
  4. The expelled gases exert a force against the launch pad. The launch pad then exerts an equal and opposite force on the rocket causing it to accelerate.
Show Only

Show Worked Solution

→ By Newton’s third law of motion (for every action there is an equal and opposite reaction), option is the correct answer.

→ Although also uses Newton’s third law, it is incorrect as it is not the launch pad exerting a force on the rocket but rather the gases expelled from the rocket.

♦ Mean mark 47%.

PHYSICS, M5 2018 HSC 21

  1. Compare the force of gravity exerted on the moon by Earth with the force of gravity exerted on Earth by the moon.   (2 marks)
  1. The acceleration due to gravity on the moon is and on Earth it is . Quantitatively compare the mass and weight of a 70 kg person on the moon and on Earth.   (2 marks)
Show Answers Only

a.   Using Newton’s Third Law:

→ The force of gravity of the Earth on the moon is equal in magnitude and opposite in direction to the force of gravity exerted on Earth by the moon.
 

b.   Comparison of mass:

→ The mass of the person on both Earth and the moon is 70 kg.

Comparison of weight:

→ The weight of the person on Earth is given by 

→ The weight of the person on the moon is given by 

→ The persons weight on Earth is greater than it is on the moon.

Show Worked Solution

a.   Using Newton’s Third Law:

→ The force of gravity of the Earth on the moon is equal in magnitude and opposite in direction to the force of gravity exerted on Earth by the moon.
 


♦♦ Mean mark (a) 33%.

b.   Comparison of mass:

→ The mass of the person on both Earth and the moon is 70 kg.

Comparison of weight:

→ The weight of the person on Earth is given by 

→ The weight of the person on the moon is given by 

→ The persons weight on Earth is greater than it is on the moon.