Newton's Second Law (including inertia) | Starter Quiz | Oak National Academy

Match the following quantities to the correct unit.

• velocity

• kilograms

• mass

• metres per second

• acceleration

• metres per second squared

• force

• metres

• displacement

• newtons

Which of the following statements about the acceleration of an object are correct?

• The greater the resultant force, the greater the acceleration of an object.

• The greater the resultant force, the lower the acceleration of an object.

• The greater the mass, the greater the acceleration of an object.

• The greater the mass, the lower the acceleration of an object.

• Acceleration is independent of mass.

Answer explanation

The acceleration is proportional to the force, so larger forces produce more acceleration. It is also inversely proportional to the mass, so larger masses produce smaller acceleration.

Which single word is used to describe slowing down due to a resultant force?

Answer explanation

Slowing down due to a resultant force is known as deceleration.

A resultant force of 20 N is used to accelerate each of the following objects. Which of the objects will be travelling fastest after 5 seconds?

• A ball of mass 0.5 kg.

• A brick of mass 1.0 kg.

• A bicycle and rider of mass 80 kg.

• A motorcycle and rider of mass 150 kg.

• A car of mass 900 kg.

Answer explanation

The smaller the mass, the greater the acceleration for a given force. That means the least massive object (the ball) will be travelling fastest after 5 seconds.

A blue and green snooker ball, of equal mass, have resultant forces acting them for 0.1 s; 20 N on the blue ball and 40 N on the green ball. Which of the following statements are correct?

• The balls will have equal acceleration.

• The green ball accelerates at a greater rate than the blue ball.

• The balls will be moving at the same speed after 0.1 s.

• The blue ball will be moving faster after 0.1 s.

• The green ball will be moving faster after 0.1s

Answer explanation

The acceleration is proportional to the force, so the green ball has a greater acceleration and will be at a higher speed after 0.1 s.

A pupil investigates how mass affects the acceleration of a trolley using hanging masses to produce a force. What should they do with a mass when they remove it from the mass holder?

• Place it safely on the desk.

• Place it on top of the trolley to keep the test fair.

• It does not matter where the mass is placed.

• Place it back on the mass holder to keep the test fair.

• Remove an equal mass from the top of the trolley.

Answer explanation

The total mass of the moving system must be kept constant for a fair test, so any mass removed from the holder needs to remain part of the system and should be placed on top of the trolley.