Forces and motion

Question 1

Mass: ?
Distance: ?
Speed: ?
Acceleration: ?
Force: ?
Time: ?
Gravity: ?

Answer 1

Mass: kilogram (kg)
Distance: metre (m)
Speed: metre per second (m/s)
Acceleration: metre per second squared (m/s^2)
Force: newton (N)
Time: second (s)
Gravity: newton/kilogram (N/kg)

Question 2

What is on the y and x axis on a d/t graph?

Answer 2

A distance time graph has distance on the y axis (usually in metres) and time on the x axis (usually in seconds)

Question 3

Which property of the d-t graph can be used to calculate speed? How do you calculate it?

Answer 3

The gradient of the line
calculation: change in y/ change in x

Question 4

What does it mean if the line is stationary on a d/t graph?

Answer 4

If the line is flat then the object is stationary.

Question 5

What is the relationship between average speed, distance moved and time taken?

Answer 5

speed (m/s) = distance travelled (m)/ time taken (s)

Question 6

What is the relationship between acceleration, change in velocity and time taken?

Answer 6

Acceleration = ((final velocity) - (initial velocity))/time = change in velocity/time

Question 7

What is on the y and x axis on a v-t graph?

Answer 7

on a velocity time graphthe velocity is on the y axis (usually in m/s) and time is on the x axis (usually in s).

Question 8

What does it mean if the line is flat on a v-t graph?

Answer 8

If the line is flat then the object is moving at a constant velocity.

Question 9

How do you find the acceleration of a v-t graph? what is the calculation?

Answer 9

The gradient of the line
calculation: acceleration= change in y/ change in x = change in velocity/time

Question 10

How do you find the total distance traveled using a v-t graph?

Answer 10

The area under the graph can be calculated as rectangles and triangles, or by counting boxes, is equal to the distance travelled.

Question 11

What is the relationship between final speed, initial speed, acceleration, and distance moved? What is v, u, a and s?

Answer 11

v= final speed
u= initial speed
a= acceleration
s= distance moved

v2=u2+2as
(final speed)2 = (initial speed)2 + (2 × acceleration × distance moved)

Question 12

In what ways can forces affect bodies?

Answer 12

force can cause an object to:
*speed up
*slow down
*change direction
*change shape (stretch, compress, or deform)

Question 13

What is tension?

Answer 13

an object that is being stretched will experience a tension force.

Question 14

What is applied force?

Answer 14

A force that is exerted on something by something else

Question 15

What is spring force?

Answer 15

A force that is exerted when a spring is squashed or stretched.

Question 16

What is drag force?

Answer 16

Force that is exerted on an object as it moves through a liquid or gas, also know as air resistance.

Question 17

What is frictional force?

Answer 17

A force that is exerted on an object in the opposite direction to weight

Question 18

What is normal force?

Answer 18

A force that is exerted on an object in the opposite direction to weight.

Question 19

What is magnetic force?

Answer 19

A force that is exerted on an object that is magnetic (either repulsion or attraction)

Question 20

what is electric force?

Answer 20

A force that is exerted on an object that is charged (either positive or negative)

Question 21

What is gravitational force?

Answer 21

Force that is exerted on all objects with mass

Question 22

What is weight?

Answer 22

downwards force due to gravity

Question 23

What is upthrust?

Answer 23

upward force that a liquid or gas exerts on a body floating in it

Question 24

What is lift?

Answer 24

force that uses motion to make an object rise up

Question 25

What are scalar and vector quantities?

Answer 25

scalars are quantities with only magnitude (size) vectors are quantities with magnitude (size) and direction

Question 26

Is force a vector or scalar quantity?

Answer 26

Force has a magnitude measured in (N) but it also has a direction, a push or a pull, up, down, left or right. So force is a vector.

Question 27

How do you calculate resultant force?

Answer 27

Forces along a line can combine by addition.

Question 28

What does it mean if the forces on both sides of the object are equal?

Answer 28

- The object is either still or moving at a constant speed - there is no resultant force - the object doesn't accelerate or decelerate

Question 29

WHat happens if there is a resultant force?

Answer 29

the objects accelerates or decelerates

Question 30

What is friction and what force does it oppose?

Answer 30

Friction is caused by surfaces rubbing. The force always acts in the opposite direction to motion.

Question 31

what is the relationship between unbalanced force, mass and acceleration?

Answer 31

Force = Mass x Acceleration.

Question 32

What is the relationship between weight, mass and gravitational field strength?

Answer 32

Weight (N)= Mass (kg) x gravitational field strength (N/kg)

Question 33

What is the gravitational field strength on earth?

Answer 33

gravitational field strength on earth is approx. 10 N/kg and in GCSEs is taken to be 10 N/kg.

Question 34

How do you calculate stopping distance?

Answer 34

Stopping distance = Thinking distance + Breaking distance

Question 35

describe the factors affecting the thinking distance:

Answer 35

Thinking distance Affected by: - Tiredness - Alcohol - speed of the car - Drugs (avoid as drugs can increase or decrease thinking distance)

Question 36

describe the factors affecting the braking distance:

Answer 36

Braking distance affected by: - Road conditions - Tyre conditions - Brake conditions - speed of the car - mass of the car

Question 37

describe the forces acting on falling objects (explain why falling objects reach a terminal velocity)

Answer 37

Initially the only force is weight as drag is proportional to velocity. So the object accelerates downwards. As it accelerates the velocity so the drag increases as well. meaning there is a smaller resultant force downwards so a smaller acceleration. Until the object reaches a speed where the drag is equal to the weight meaning there is no acceleration, this velocity is know as terminal velocity.

Question 38

What is Hooke's law?

Answer 38

Hooke’s law is that extension is directly proportional to force applied. This is shown by the straight line on the force-extension graph. Hooke’s law is obeyed as long as the line is straight.

Question 39

What is elastic behavior? What is elastic limit?

Answer 39

An object that can be described as having elastic behavior is an object that when it is pulled or stretched, it doesn't break, so when the forces are removed, it will return to its original state, in a spring this occurs when the force is lower than the elastic limit. Elastic Limit When the material is stretched too far and loses its elasticity and reached its elastic limit. It is unable to return to its original shape.

Question 40

What are the 2 forces falling object experience?

Answer 40

- weight (due to gravity) - air resistance (due to friction)

Question 41

Explain what happens to the air resistance and weight on an object as it falls:

Answer 41

- Initially, the upwards air resistance is very small because the skydiver isn't falling very quickly - an unbalanced force object will accelerate downwards (there is a resultant force) - As the skydiver speeds up, the air resistance increases eventually growing large enough to balance the downward weight force - no more resultant force and there is no acceleration so the object is traveling at a constant speed (which is known as terminal velocity)

Question 42

What does hookes law state?

Answer 42

The extension of an elastic object is directly proportional to the force applied, up to the limit of proportionality. Directly proportional means that as more force is applied, the greater the extension (and vice versa)

Question 43

What is the limit of proportionality?

Answer 43

The limit of proportionality is where if more force is added, the object may extend but will not return to its original shape when the force is removed (it will be inelastically deformed) - This limit varies according to the material

Question 44

What is the relationship between force and extension called according to Hooke's law?

Answer 44

Hooke’s law is the linear relationship between force and extension: - This is represented by a straight line on a force-extension graph

Question 45

Examples of materials that undergo elastic deformation are:

Answer 45

Rubber bands Fabrics Steel springs

Question 46

Examples of materials that undergo inelastic deformation are:

Answer 46

Plastic Clay Glass