Forces and Motion

Question 1

What the equation relating velocity, displacement and time

Answer 1

velocity = displacement/time

Question 1

What is the equation relating speed distance and time

Answer 1

Speed = distance/time

Question 2

What is the equation for acceleration

Answer 2

a=v-u/t

Question 3

In the acceleration equation what do v and u represent

Answer 3

v= final velocity
u = start velocity

Question 4

In a distance time graph how do you find the velocity

Answer 4

gradient of the line

Question 5

In a distance time graph what does a flat section represent

Answer 5

Stopped

Question 6

In a distance time graph what does a straight line at an angle represent

Answer 6

constant velocity

Question 7

In a distance time graph what does a curve represent

Answer 7

acceleration

Question 8

In a distance time graph what does a curve that is levelling off represent

Answer 8

deceleration

Question 9

In a velocity time graph what does a line going uphill represent

Answer 9

acceleration

Question 10

In a velocity time graph what does a flat line represent

Answer 10

steady speed

Question 11

In a velocity time graph what does a curve represent

Answer 11

change in acceleration

Question 12

In a velocity time graph what does a line going down hill represent

Answer 12

deceleration

Question 13

How would you calculate the distance travelled in a distance time graph

Answer 13

the area under the graph

Question 14

In a velocity time graph what does the gradient equal

Answer 14

acceleration

Question 15

What is the equation for acceleration when final velocity is the subject

Answer 15

V= u+at

Question 16

What is a vector

Answer 16

It has size and direction

Question 17

What is a scalar

Answer 17

It only has size

Question 18

Explain what happens when someone jumps out of a plane in terms of terminal velocity

Answer 18

• When the person first jumps there weight is larger then drag so there is a resultant force - so they are accelerating downwards
• As the speed increases so does the drag and eventually they are equal. This means there is no acceleration, no resultant force and they are travelling at a constant velocity (they have reached terminalvelocity)
• When parachute is pulled there is more drag so there is a resultant force upwards so they decelerate until forces are equal and reach terminal velocity again

Question 19

What are the 2 equations that concern Newtons 2nd law

Answer 19

W=mg
F=ma

Question 20

In the equation F=ma what does each letter stand for

Answer 20

F= resultant force
m=mass
a= acceleration

Question 21

W=mg - what is the value of g

Answer 21

10m/s2

Question 22

What do resultant forces cause

Answer 22

They cause an object to accelerate or decelerate

Question 23

What happens if there is no resultant force

Answer 23

On object will stay still or if they are already moving they will move at a constant velocity

Question 24

What is a force and what are there effects

Answer 24

A force is a push or a pull Forces make a body: change speed, change shape or change direction

Question 25

Name 4 types of forces

Answer 25

1. Friction 2. Upthrust 3. weight/ gravitational force 4. drag/ air resistance

Question 26

What is the equation for work done

Answer 26

work done = force x distance

Question 27

What is thinking distance

Answer 27

The distance a car travels whilst the driver reacts to the incident

Question 28

What is braking distance

Answer 28

It is the distance a car travels once the brakes have been applied until the car is stationary

Question 29

What is stopping distance

Answer 29

braking distance added to the thinking distance

Question 30

What affects thinking distance

Answer 30

- speed - distractions - fatigue - alcohol or drug intake

Question 31

What affects braking distance

Answer 31

- speed - mass of the car - road surface - if the road is wet or icy - quality of the tyres and brakes

Question 32

How does speed affect the braking distance

Answer 32

work done by brakes = the kinetic energy transferred Fxs= mv2/2 so s depends on v2 (assume F and m are constant

Question 33

What is the relationship between speed and thinking distance

Answer 33

They are directly proportional

Question 34

What is newtons first law

Answer 34

A body stays at rest or moves with a constant velocity unless a resultant force acts upon it

Question 35

Newtons third law

Answer 35

Every action force has a equal and opposite reaction force

Question 36

What is the equation relating velocity acceleration and distance

Answer 36

v2 = u2 + 2as