Forces And Motions

Question 1

How do you know if an object has stopped obeying Hooke’s law

Answer 1

On a graph, the straight-line relationship would have stopped meaning it has reached its elastic limit

Question 2

Key things about distance- time graphs

Answer 2

1. Gradient= speed
2. Steeper the graph the faster it’s going
3. Downhill sections means it’s going back to the start

Question 3

Key things about velocity-time graphs

Answer 3

1. Gradient = acceleration
2. Flat sections represent steady speed
3. Steeper the graph the greater the acceleration/deceleration
4. Downhill sections mean deceleration
5. Area under graph is distance travelled

Question 4

Describe how terminal velocity can be reached on a falling object

Answer 4

1. Only weight force is acting on the object causing them to accelerate
2. Gradually air resistance becomes greater, it’s still speeding up just at a slower rate
3. When the air resistance and weight force level out, the object has reached its terminal velocity
4. When a parachute is released air resistance has increased because the surface area has increased
5. Eventually, by the time you reach the ground your weight and air resistance would have even out

Question 5

Newton’s first law

Answer 5

Balanced forces means no change in velocity

Question 6

Newton’s second law

Answer 6

If there is an unbalanced force, then the object will accelerate in that direction

Question 7

What can affect your braking distance

Answer 7

1. How fast your going
2. Mass of the vehicle
3. How good the brakes are
4. How good the grip is on your tyres

Question 8

What is a moment

Answer 8

It’s a turning effect of a force

Question 9

How do you get the maximum moment

Answer 9

You push it at right angles (perpendicular) to the object

Question 10

What is the asteroid belt and how can asteroids hit other planets

Answer 10

• It’s between Mars and Saturn
• Majority of the time the asteroids stay in a stable orbit but it’s motion can get disrupted by a collision/ gravitational interaction

Question 11

Difference between a solar and lunar eclipse

Answer 11

Solar: sun, moon, Earth
Lunar: sun, Earth, moon

Question 12

What are gas giants and give examples

Answer 12

• they are planets made primarily up of hydrogen

* Jupiter, Uranus, Saturn and Neptune

Question 13

Key things about comets

Answer 13

• They are highly elliptical

* Towards the Sun they accelerate due to gravity and they decelerate away from the Sun

Question 14

Hooke’s law

Answer 14

The extension is proportional to the force