Sp2- motion and forces

Question 1

What does a straight uphill section show on a dist time graph?

Answer 1

It is travelling at a steady speed

Question 2

What does it mean if the line is getting steeper on a dist time graph?

Answer 2

The faster it is going

Question 3

What do flat sections mean on a dist time graph?

Answer 3

This is when the object is stationary

Question 4

What does a steepening curve show on a dist time graph?

Answer 4

That it is accelerating

Question 5

What does a levelling off curve show on a dist time graph?

Answer 5

It is decelerating

Question 6

How do you work out the speed on a dist time graph?

Answer 6

The gradient of the line

Question 7

How do you find the speed of a curved line on a dist time graph?

Answer 7

You draw a tangent to the curve and work out the gradient of the line

Question 8

What does a flat line show on a velocity time graph?

Answer 8

It is travelling at a steady speed

Question 9

What does a steep line on a velocity time graph show?

Answer 9

The steeper the line, the greater the acceleration

Question 10

What do downhill sections on a velocity time graph?

Answer 10

That it is decelerating

Question 11

What does a curved line show on a velocity time graph?

Answer 11

That it is changing acceleration

Question 12

How do you work out the acceleration of a velocity time graph?

Answer 12

You work out the final velocity - the initial velocity and divide it by the time it takes

Question 13

How do you work out the dist travelled of a velocity time graph?

Answer 13

Work out the area underneath the graph

Question 14

What is a resultant force?

Answer 14

If you have a number of forces acting on a single point and you can replace them by a single force which has the same effect as the original forces acting together

Question 15

What is Newton’s first law?

Answer 15

That a resultant force is needed to change the motion of an object and a force is needed to change the speed of direction of the object

Question 16

What will happen if a stationary object has a zero resultant force?

Answer 16

It will remain stationary

Question 17

What happens if you have a zero resultant force on a moving object?

Answer 17

It will just carry on at a steady velocity

Question 18

What happens if there is a non zero resultant force on an object?

Answer 18

It’s velocity will change so the object will either change speed or direction as velocity is a vector

Question 19

What is Newton’s Second Law?

Answer 19

The larger the force, the larger the acceleration as they are directly proportional to each other

Acceleration is inversely proportional to mass so if you have an object with a larger mass it will accelerate less than an object with a smaller mass

Question 20

Why do centripetal forces occur?

Answer 20

As when an object is travelling in a circle it is constantly changing direction and speed so it is changing velocity and therefore accelerating. There must be a resultant force being constantly applied to the object

Question 21

What is an objects inertial mass?

Answer 21

How difficult it is to change the velocity of an object.

A bigger force needs to be applied to an object with a larger mass in order to change its velocity

Question 22

Core Practical:

How does the weight of the trolley affect the experiment?

Answer 22

The weight of the trolley down the slope compensated for the friction acting between the wheels of the trolley and the ramp.

Question 23

Core Practical:

How do you work out the velocity of the experiment?

Answer 23

You measure the length of the card and divide it by the duration of the interruption

Question 24

Core Practical:

How do you work out the acceleration of the experiment?

Answer 24

You work out the velocity of the final gate and minus it from the velocity of the first gate and divide it by the time

Question 25

Core Practical:

How can you reduce friction of the experiment?

Answer 25

You use an air slope to reduce friction

Question 26

Core Practical:

How do you vary the mass of the experiment?

Answer 26

You add masses to the trolley one at a time to increase the mass of the system

Question 27

Core Practical:

How do you vary the force of the experiment?

Answer 27

You keep the total mass of the system the same and change the weight of the hook

Question 28

Core Practical:

Why is a light gate used rather than a stopwatch?

Answer 28

As measurements aren’t affected by reaction times

Question 29

Core Practical:

How can you use a video camera to determine an objects speed?

Answer 29

You could work out the number of frames per second and you can find out the dist travelled by an object by knowing the time of the object

Question 30

What is Newton’s Third Law?

Answer 30

When two objects interact, they exert equal but opposite forces of the same type on each other

Question 31

How is equilibrium different to Newton’s Third Law?

Answer 31

As with equilibrium the objects are experiencing a zero resultant force and these forces could be different whereas with newton’s third law they are same type of forces

Question 32

How does Newton’s third law affect momentum?

Answer 32

Newton’s third law causes opposite but equal forces to act which causes a change in momentum and these equal but opposite forces lead to the conservation of momentum in a collision