20 Practice Questions for Year 11 Physics Module 2: Dynamics

Question 6

Two blocks, 3kg and 5kg are on a double inclined slope connected to each other with a rope and frictionless pulley. The 3kg block is inclined at an angle of 60 degrees and the 5kg block is inclined at an angle of 30 degrees. Calculate the acceleration of the blocks then calculate the tension in the rope.

 

Investigate, describe and analyse the acceleration of a single object subjected to a constant net force and relate the motion of the object to Newton’s Second Law of Motion (ACSPH062, ACSPH063)

Question 7

When an object breaks into two pieces, the lighter fragment gets more kinetic energy than the heavier one. This is a result of the conservation of momentum. Explain it using Newton’s laws of motion.

 

Apply Newton’s first two laws of motion to a variety of everyday situations, including both static and dynamic examples

Question 8

A 6.00kg box sits on an incline of 40 degrees against the horizontal. The coefficient of kinetic friction between the box and incline is 0.40. What is the horizontal force required to move the box up the in line with a constant acceleration of 4.2 ms-2?

 

Apply Newton’s first two laws of motion to a variety of everyday situations, including both static and dynamic examples, and include the role played by friction (ACSPH063)

Momentum, Energy and Simple Systems

Question 9

When splitting logs, a heavier hammer is more effective than a lighter one. Why is this so?

 

Conduct an investigation to describe and analyse one-dimensional (collinear) and two-dimensional interactions of objects in simple closed systems (ACSPH064)

Question 10

Explain the use of crumple zones and airbags in cars for safety reasons. Make reference to Newton’s three laws of motion as well as the concept of impulse.

 

Evaluate the effects of forces involved in collisions and other interactions, and analyse quantitatively the interactions using the concept of impulse

Question 11

In a rescue operation, a team of firefighters is trying to reach the top floor of a building. One scales the walls of the building, the other takes the winding stairs outside the building and one takes the stair that go directly to the top floor. Which one does the most work? Provide reasons for your answer.

 

Apply the special case of conservation of mechanical energy to the quantitative analysis of motion

Question 12

A 30 kg object is sliding down a horizontal surface at 10ms-1 and stops due to friction. The coefficient of kinetic friction between the object and the surface is 0.2. What is the average power produced by the friction as the object stops?

 

Conduct investigations over a range of mechanical processes to analyse qualitatively and quantitatively the concept of average power

Question 13

A 20.0kg child plays on a swing with 2.00m support ropes. The brother pulls the child back until the roes are 45 degrees from the vertical and releases it from rest. What is the potential energy just as the child is released compared to the potential energy at the bottom of the swing’s motion?

 

Apply the special case of conservation of mechanical energy to the quantitative analysis of motion

Question 14

Consider a collision between a 1000kg car travelling 20ms-1 to the North and a small truck with a mass of 3000kg travelling 15ms-1 East. If the car and truck join together due to the collision, what is their final velocity?

 

Analyse quantitatively and predict, using the law of conservation of momentum (ACSPH066)

Question 15

If the momentum of a pair of objects is zero, must the kinetic energy of those objects also be zero? Explain your reasoning.

 

Analyse quantitatively and predict, using the law of conservation of momentum

Question 16

A machine gun is fired at piece of metal. Is the average force on the metal greater if the bullets bounce off, or if they are embedded into the plate? Explain your reasoning.

 

Analyse and compare the momentum and kinetic energy of elastic and inelastic collisions

Question 17

In a big waterfall, the water directly underneath gets heated up. Explain how this occurs.

 

Apply the special case of conservation of mechanical energy to the quantitative analysis of motion

Question 18

A box slides down an incline and work is done on the box by the gravitational force as well as the frictional force. Can the work done be expressed in terms of a change in potential energy? Explain your reasoning.

 

Apply the special case of conservation of mechanical energy to the quantitative analysis of motion

Question 19

A worker horizontally pushes a 30.0 kg crate a distance of 5.0 m along a level floor at a constant velocity. The coefficient of kinetic friction between the crate and the floor is 0.30. What is the total work done on the crate?

 

Apply the special case of conservation of mechanical energy to the quantitative analysis of motion

Question 20

An object is pulled by having a rope attached to it, causing it to accelerate. However, according to Newton’s third law, the object pulls back on the rope with a force of equal magnitude and opposite direction. Is the total work done then zero? If so, how does the kinetic energy of the body change?

 

Apply the special case of conservation of mechanical energy to the quantitative analysis of motion