Unit 1 Forces and Motion

Question 1

What is a distance time graph?

Answer 1

A graph in which measures how far something travels in a certain period of time, and the different speeds that occur at different stages.

Question 2

What does the gradient of a line represent in a distance time graph?

Answer 2

The speed of which the object is travelling at

Question 3

What is the formula for speed?

Answer 3

change in distance/change in time = speed

s = d/t

Question 4

What does a straight diagonal line represent in a distance time graph?

Answer 4

Constant Speed

Question 5

What does a straight horizontal line represent in a distance time graph?

Answer 5

Stationary

Question 6

What is the speed of an object that is stationary?

Answer 6

0m/s

We know this because the gradient of a straight horizontal line is 0 in a distance time graph (gradient = speed)

Question 7

What does a curve up mean in a distance time graph?

Answer 7

Acceleration: Gradient/Speed is increasing

Changing speeds

Question 8

What does a curve down mean in a distance time graph?

Answer 8

Deceleration: Gradient/Speed is decreasing

Changing speeds

Question 9

How do you find the gradient of a curve in a distance time graph?

Answer 9

You can draw a tangent (a straight line on the curve) and figure out the gradient from the line onwards.

Question 10

Which axis do the distance and time go in a distance time graph?

Answer 10

Time = x axis
Distance = y axis

Question 11

What is the formula for acceleration when you are given the time?

Answer 11

acceleration (m/s2) = change in velocity (m/s) / time (s)

Question 12

How can you find the change in velocity?

Answer 12

v - u
final velocity - initial velocity

Question 13

Is acceleration a vector or scalar quantity? What does this mean?

Answer 13

Vector quantity

Meaning it have a number and a direction. We show the direction by using negative or positive numbers.

Positive = Accelerating
Negative = Decelerating

Question 14

When you calculate the acceleration, is it accurate?

Answer 14

No, because it is just the average velocity in that period of time.
If the line in the distance time graph was straight diagonal - that means it is constant. Meaning that the rate of acceleration is the same throughout.
But if the line were a curve then the rate of acceleration wouldn’t be the same throughout. It could be different velocities at different stages averaged out together.

Question 15

What is acceleration?

Answer 15

The rate of change in velocity. How quickly something can speed up or slow down.

Question 16

What is the formula for acceleration when you are given the distance/

Answer 16

2a (m/s2) s (m) = v2 - u2 (m/s)

Question 17

What is the a velocity of an object that’s initial velocity is stationary?

Answer 17

0m/s

Question 18

What is a velocity time graph?

Answer 18

A graph that measures how an objects velocity changes overtime.

Question 19

In a velocity time graph, which axis do the velocity and time go?

Answer 19

Velocity = y axis
Time = x axis

Question 20

What does the gradient represent in a velocity time graph?

Answer 20

acceleration = change in velocity/change in time

Question 21

What does a constant positive gradient represent (upwards diagonal line) in a velocity time graph?

Answer 21

Constant acceleration

Question 22

What does a constant negative gradient represent (downwards diagonal line) in a velocity time graph?

Answer 22

Constant deceleration

Question 23

What does the flat sections represent in a velocity time graph?

Answer 23

Constant velocity

Question 24

How do you calculate the distance travelled in a velocity time graph?

Answer 24

By finding the area under the curves/lines - answer in meters.

*To calculate area under curve lines just count the boxes that make up the area - not accurate but it’s fine.

Question 25

What is the formula for weight?

Answer 25

w = m x g weight = force g = 9.8N or 10N

Question 26

What do forces do to objects?

Answer 26

forces can change the speed (accelerate), the shape (stretch/compress) and the direction of objects

Question 27

What are the types of forces?

Answer 27

gravitational force, electrostatic force, frictional force, applied force, tension force and normal force

Question 28

What is gravitational force?

Answer 28

the force of attraction between 2 objects mass

Question 29

What is electrostatic force?

Answer 29

the force between electrically charged objects

Question 30

What is frictional force?

Answer 30

the force opposing the motion of objects when rubbed together

Question 31

What is applied force?

Answer 31

force exerted by a person/object

Question 32

What is normal force?

Answer 32

force exerted by the surface to support the weight of the object on it

Question 33

What is tension force?

Answer 33

force transmitted by a string when pulled on both ends

Question 34

What force a vector or scalar quantity?

Answer 34

vector quantity because it have a magnitude and direction

Question 35

What is the resultant force?

Answer 35

total amount of force acting on an object along with the direction

Question 36

What is the resultant force of an object at rest?

Answer 36

0N

Question 37

How do you calculate the resultant force?

Answer 37

add all the magnitudes if the forces are in the same direction. however if the forces are in different directions subtract the magnitudes.

Question 38

What is friction?

Answer 38

the force that acts between 2 surfaces when in contact with each other. it opposes motion between them and can slow it down.

Question 39

What does the force of friction depend on?

Answer 39

the normal force acting on it pushing them together

Question 40

What is stopping distance?

Answer 40

the time it takes for a driver to stop their car when it finds out it needs to

Question 41

What is the formula for stopping distance?

Answer 41

stopping distance = thinking distance + braking distance

Question 42

What is the thinking and braking distance?

Answer 42

thinking distance: distance travelled during the drivers reaction time realising to stop braking distance: distance travelled from when the driver applied brakes to when the car stops.

Question 43

What are the factors affecting stopping distance?

Answer 43

speed, mass, road conditions, reaction time

Question 44

What is Hooke's law?

Answer 44

force and extension are directly proportional up until the elastic limit

Question 45

What is the formula for Hooke's law?

Answer 45

force = spings constant x springs extension f=kx

Question 46

What is elastic behaviour?

Answer 46

the ability of an object to go back to its original shape after the forces applied causing deformation have been removed. this is because the particles in the material can act like springs.

Question 47

What is the elastic behaviour for helical springs?

Answer 47

springs are elastic and always come back to original shape after the forces are removed. however only up until the elastic limit, this is the point where too much force is applied and the spring come back longer than it was before.

Question 48

What is the elastic behaviour for metal wires?

Answer 48

a metal wire will go back to its original shape except if the force applied exceeds its elastic limit - it will break. (breaking point)

Question 49

What is the elastic behavior for rubber bands?

Answer 49

a rubber band will go back to its original shape except if the force applied exceeds its elastic limit - it will break.