Forces

Question 1

What is happening if the resultant force is 0 on a stationary object

Answer 1

It stays stationary

Question 2

What is the resultant force

Answer 2

The sum of the forces

Question 3

What happens to a moving object if the resultant force is 0?

Answer 3

It keeps moving at a constant speed

Question 4

What happens when the forces aren’t balanced in a stationary object

Answer 4

It begins to move in the direction of the resultant force

Question 5

What happens to a moving object when the resultant force isn’t 0

Answer 5

It accelerates or slows down depending on the direction of the resultant force

Question 6

What does acceleration depend on?

Answer 6

Size of the force

The mass

Question 7

What is acceleration measured in?

Answer 7

M/s2

Question 8

What is velocity measured in?

Answer 8

M/s

Question 9

How do you find the distance travelled in a velocity time graph

Answer 9

The area under the graph is the total distance travelled

Question 10

What is Newton’s first law?

Answer 10

Object stays still unless acted on by unbalanced forces

Question 11

What is Newton’s third law?

Answer 11

If a body exerts a force on another, there is an equal and opposite force

Question 12

What is force measured in?

Answer 12

N Newton’s

Question 13

When there is a horizontal line on a velocity time graph, what does that mean?

Answer 13

Object is moving at a constant speed

Question 14

When there is a horizontal line on a distance time graph, what does that mean?

Answer 14

Object is stationary

Question 15

When there is a straight diagonal line going up on a distance time graph, what does that mean?

Answer 15

Object is moving at a steady speed (constant speed)

Question 16

When there is a straight diagonal line going up on a velocity time graph, what does that mean?

Answer 16

Object is moving at a constant acceleration

Question 17

When there is a curved line going up on a distance time graph what does that mean?

Answer 17

Object is accelerating

Question 18

When there is a curved line going down in a distance time graph what does that mean?

Answer 18

Object is decelerating

Question 19

When there is a curved line going up on a velocity time graph, what does that mean?

Answer 19

Increased rate of acceleration

Question 20

When there is a curved line on a velocity time graph going down, what does that mean?

Answer 20

Increased rate of deceleration

Question 21

When there is a diagonal line going down on a velocity time graph what does that mean?

Answer 21

Constant deceleration of object

Question 22

When there is a diagonal line going down on a distance time graph, what does that mean?

Answer 22

Object is travelling at a steady speed (constant speed) back to the start

Question 23

The steeper the Line…

Answer 23

The greater the acceleration

Question 24

How do you calculate the gradient?

Answer 24

Rise/run

Question 25

What does working out the gradient represent on a velocity time graph

Answer 25

The acceleration

Question 26

What does the stopping distance of a car depend on ?

Answer 26

Thinking distance and braking distance

Question 27

What 5 forces act on a car moving at a steady speed?

Answer 27

``` Weight Reaction force Driving force Friction Air resistance ```

Question 28

Which force on a car is pointed down?

Answer 28

Weight (gravity)

Question 29

Which force on a car is pointing up?

Answer 29

Reaction force

Question 30

Which forces on a car are indirectly proportional?

Answer 30

Weight(gravity) and reaction force Driving force and air resistance

Question 31

Format in drawing resultant force?

Answer 31

E.g. 2N^ 3N>

Question 32

If the driving force is bigger than the air resistance of a car moving, what is the car doing ?

Answer 32

Accelerating

Question 33

For a car to slow down, what has to happen (2)

Answer 33

The driving force must be reduced The resistive forces must be increased

Question 34

How do you work out stopping distance?

Answer 34

Stopping distance= thinking distance+breaking distance

Question 35

What is thinking distance?

Answer 35

Distance travelling between need for breaking and brakes being pressed

Question 36

What is breaking distance ?

Answer 36

Distance taken to stop after brakes have been applied

Question 37

What 3 factors affect thinking distance?

Answer 37

Tired Distracted Influence from drugs and alcohol

Question 38

What 2 factors affect breaking distance?

Answer 38

The cars tyres or brakes are in poor condition Weather conditions I.e. Icy roads

Question 39

What happens when the braking distance increases?

Answer 39

Car's speed increases

Question 40

What happens when brakes are applied to a car? (3)

Answer 40

Work is done by the friction force Kinetic energy of the vehicle is reduced because the speed decreases Increases temperature of the brakes

Question 41

What is terminal velocity ?

Answer 41

When the resultant force is 0

Question 42

What are the main 2 forces exerted on falling objects ?

Answer 42

Weight(gravity) Air resistance

Question 43

What are the 3 stages of falling (3)

Answer 43

Since in1) object accelerates downwards No air resistance 2) air resistance increases and becomes bigger than the weight/ force 3) the object's weight and air resistance is balanced. It reaches a steady speed called terminal velocity

Question 44

Why does a coin fall faster than a feather ?

Answer 44

The feather is lighter so air resistance increases quickly and it falls at terminal velocity The coin is heavier so it travels fast before air resistance is large enough to balance the weight. So, it probably hits the ground before terminal velocity

Question 45

On the moon, what happens when you drop a light object and a heavy object and why?

Answer 45

They land at the same time. The moons gravity is too weak so there is no air resistance. Therefore, the objects had the same acceleration

Question 46

On a velocity time graph for falling objects, when a line is horizontal, what does it mean?

Answer 46

Object has reached terminal velocity

Question 47

What are the 3 stages of dropping something?

Answer 47

1) object accelerates because the force of gravity is bigger than friction force 2) it is still accelerating but acceleration decreases as friction is increasing 3) it stops accelerating and reaches terminal velocity

Question 48

What is the difference between weight and mass ?

Answer 48

Weight is the result of gravity and is the force acting on mass. measures in N Mass is how much stuff is in an object measure in kg

Question 49

What do elastic objects do?

Answer 49

Store elastic potential energy when stretched

Question 50

What is the relationship between the extension of an elastic object and the force applied?

Answer 50

They are directly proportional

Question 51

What is the spring constant measured in?

Answer 51

N/m

Question 52

The greater the spring constant...

Answer 52

The greater the value of K so the stiffer the spring