What is meant by the weight of an object?

• the gravitational field acting on the object

• the gravitational force acting on the object

• the mass of the object multiplied by gravity

• the object’s mass multiplied by its acceleration

A cyclist is riding at a steady speed on a level road. According to Newton’s third law of motion, what is equal and opposite to the backward push of the back wheel on the road?

• the force exerted by the cyclist on the pedals

• the forward push of the road on the back wheel

• the tension in the cycle chain

• the total air resistance and friction force

A force F is applied to a freely moving object. At one instant of time, the object has velocity v and acceleration a. Which quantities must be in the same direction?

• a and v only

• a and F only

• v and F only

• v, F and a

Which is not one of Newton's laws of motion?

• A body continues in a state of rest or of uniform motion in a straight line unless acted upon by some external force

• If body A exerts a force on body B, then body B exerts an equal and oppositely-directed force on body A.

• The total momentum of a system of interacting bodies remains constant, providing no external force acts.

• The rate of change of momentum of a body is directly proportional to the external force acting on the body and takes place in the direction of the force.

A mass accelerates uniformly when the resultant force acting on it ....

• is proportional to the displacement from a fixed point

• increases uniformly with respect to time

• is constant but not zero.

• is zero.

Which of the following is a statement of the principle of conservation of momentum?

• Momentum is the product of mass and velocity.

• In an elastic collision, momentum is constant.

• The momentum of an isolated system is constant.

• The force acting on a body is proportional to its rate of change of momentum.

In perfectly elastic collisions between two atoms, it is always true to say that ....

• the initial speed of one atom will be the same as the final speed of the other atom.

• the relative speed of approach between the two atoms equals their relative speed of separation.

• the total momentum must be conserved, but a small amount of the total kinetic energy may be lost in the collision.

• whatever their initial states of motion, neither atom can be stationary after the collision

Which statement describes the mass of an object?

• the force the object experiences due to gravity

• the momentum of the object before a collision

• the weight of the object as measured by a balance

• the resistance of the object to changes in motion

Their initial speeds are uX and uY respectively. After the collision they move apart with speeds vX and vY respectively. Their directions are shown. Which equation is correct?

• uX + uY = vX + vY

• uX + uY = vX – vY

• uX – uY = vX + vY

• uX – uY = vX – vY

A ball is falling at terminal speed in still air. The forces acting on the ball are upthrust, viscous drag and weight. What is the order of increasing magnitude of these three forces?

• upthrust -> viscous drag -> weight

• viscous drag -> upthrust -> weight

• viscous drag -> weight -> upthrust

• weight -> upthrust -> viscous drag