C8 NEWTONS LAWS OF MOTION

Question 1

What does Newton’s first law state? (1)

Answer 1

⇒ Objects either stay at rest or move with a constant velocity unless acted on by an external force (1)

Question 2

What does Newtons second law state, give the formula (2)

Answer 2

⇒ Force ∝ acceleration, given that mass is a constant (1)

⇒ F = ma (1)

Question 3

State the formula for Newtons second law of motion, giving its units. (1)

Answer 3

⇒ Force = Mass x Acceleration (1)
Where;
Force = F (N)
Mass = m (kg)
Acceleration = (ms⁻²)

Question 4

State the formula for weight. (1)

Answer 4

⇒ Weight (W/N) = mass (m/kg) x Gravitational field strength (g/N kg⁻¹) (1)

Question 5

State Newtons 3rd law of motion. (1)

Answer 5

⇒ Every action has an equal and opposite reaction (1)

Question 6

What are the two main types of friction, explain their difference? (2)

Answer 6

⇒ Contact friction: occurs between solid surfaces (1)

⇒ Drag: occurs between fluids (liquid or gas) (1)

Question 7

State three facts about frictional forces. (3)

Answer 7

⇒ They only act in the opposite direction of a moving object (1)
⇒ They can never speed things up or start to make something move (1)
⇒ They convert kinetic energy into heat (1)

Question 8

What does drag force depend on? (3)

Answer 8

⇒ The shape of an object (1)
⇒ The speed (1)
⇒ The viscosity of the fluid (1)

Question 9

Define and explain lift. (3)

Answer 9

⇒ An upwards force on an object moving through a fluid (1)
⇒ Occurs when the shape of an object causes the fluid flowing over it to change direction. (1)
⇒ The force acts perpendicular to the direction in which the fluid is flowing (1)

Question 10

Define terminal velocity. (1)

Answer 10

⇒ When the frictional forces = driving forces (1)

Question 11

How do we increase the maximum velocity? (2)

Answer 11

⇒ Increase the driving force (increase engine size) (1)

⇒ Reducing the frictional force (making body more streamlined) (1)

Question 12

How does a parachute effect the terminal velocity? (4)

Answer 12

⇒ Air resistance overcomes the weight of parachutist (1)
⇒ Air resistence > weight (1)
⇒ Acceleration upwards (1)
⇒ Parachustist slows down (1)

Question 13

Define thinking distance. (1)

Answer 13

⇒ The distance travelled by a vehicle in the time it takes the driver to react. (1)

Question 14

Define braking distance. (1)

Answer 14

⇒ The distance travelled by car in the time it takes to stop safely, from when the brakes are first applied. (1)

Question 15

State the formula for stopping distance. (1)

Answer 15

⇒ Stopping distance = thinking distance + braking distance (1)

Question 16

State 5 factors that may affect the thinking distance. (5)

Answer 16

⇒ Influence of drugs/alcohol
⇒ Distractions
⇒ Age
⇒ Tiredness/fatigue
⇒ Speed

Question 17

State 4 factors that may affect the breaking distance (4)

Answer 17

⇒ Poor weather conditions (1)
⇒ Rain/Wet/slippery conditions (1)
⇒ Poor brakes (1)
⇒ Worn out tyres (1)