Newtons laws

Question 1

EQ. Explain a balanced and unbalanced force, using a practical example for each. (4 marks)

Answer 1

• no net force and stationary
• e.g a runner at constant velocity
• net force is present and accelerating
• e.g a tennis serve

Question 2

EQ. Define Newton’s third law of motion and apply it to a sporting example of your choice. (3 marks)

Answer 2

• for every force there is an equal and opposite reaction force
• e.g when you apply a force to a netball
• the netball shot applies an equal and opposite reaction force to the netball shooter

Question 3

Define newtons first law

Answer 3

a body continues in uniform velocity unless acted on by an external force

Question 4

EQ. Explain why newtons first law applies to a golf ball on the tee. (2 marks)

Answer 4

-the ball will remain at rest on the tee until its struck by a gold club (external force)

Question 5

EQ. Apply newtons second law of motion to show how a hockey player may maximise the ball’s acceleration. (3 marks)

Answer 5

• the force applied will be proportional to the acceleration
• the more force applied to the hockey ball the faster the velocity will be
• the size of the force depends on the velocity of the stick

Question 6

EQ. Calculate the force applied to a hockey ball with a mass of 0.16kg to cause it to accelerate at a rate of 30m/s/s. (2 marks)

Answer 6

• force = mass x acceleration
• 0.16 x 30
• 4.8 kgms/s

Question 7

Define newtons second law

Answer 7

the acceleration or velocity of a body is proportional to the size of the force

Question 8

Define newtons third law

Answer 8

for every action or force there is an equal and opposite reaction

Question 9

EQ. Apply Newton’s third law of motion to a footballer heading a ball. (3 marks)

Answer 9

• player applies a force to the ball
• football applies an equal force to the head
• football applies an opposite force to the head