P2.1

Question 1

What is an example of magnetism

Answer 1

A metal car being attracted to a magnet; the magnet is attracted to the car with equal and opposite force

Question 2

What is an example of gravity

Answer 2

A ball being attracted for the planet; the planet is attracted to the ball with an equal and opposite force but the ball has a much smaller mass so it’s the ball that moves

Question 3

What is equal and opposite force

Answer 3

The same force acting on different objects

Question 4

What is a resultant force

Answer 4

The sum of different forces acting on the same object

Question 5

What do we call it if the resultant force is zero

What do we call it if the resultant force is not zero

Answer 5

We say that the forces are balanced

We say that the forces are unbalanced

Question 6

What happens of the resultant force is zero

Answer 6

If the object is not moving it stays where it is

If the object is moving it keep moving at the same speed in the same direction

Question 7

What happens if the resultant force is not zero

Answer 7

The object will accelerate in the direction of the resultant force

Object will accelerate in the direction of the resultant force, making it slow down, speed up or change direction

Question 8

What does the acceleration of an object depend on

Answer 8

The size of the unbalanced force- the bigger the force the greater the acceleration

The mass of the object- the bigger the mass, the smaller the acceleration

Question 9

What is the formula for resultant force

Answer 9

Resultant force (N) = Mass (kg) X Acceleration (m/s2)

Question 10

What is the formula for speed

Answer 10

Speed (m/s) = Distance (m)

Time (s)

Question 11

What is velocity

Answer 11

Speed with a direction

Question 12

What is acceleration

Answer 12

The rate at which its velocity changes

Question 13

What is the formula for acceleration

Answer 13

Acceleration (m/s2) =
                  Velocity change (m/s)
               Time taken for change (s)

Question 14

What needs to happen for a car to stop

Answer 14

It needs to lose all its kinetic energy

Question 15

What happens when the breaks are applied

Answer 15

They work to transfer the kinetic energy of the vehicle into heat energy in the brakes. The breaks therefore increase temperature

Question 16

What does the stopping distance of a vehicle depend on

Answer 16

Thinking distance

Braking distance

Question 17

What’s thinking distance

Answer 17

The distance travelled by the vehicle from the point when the driver sees that he needs the stop to when he actually applies the breaks

Question 18

What’s breaking distance

Answer 18

The distance travelled by the vehicle from the point when the driver applies the breaks to where the vehicle actually stops

Question 19

Factors affecting thinking distance

Answer 19

Tiredness
Influence of drugs or alcohol
Being distracted e.g. By mobile phone or passengers

Question 20

Factors affecting breaking distance

Answer 20

Adverse weather conditions e.g. Wet or icy roads

Poor conditions of vehicle e.g, brakes and tyres

Question 21

What two forces do falling objects experience

Answer 21

Downwards force of weight

The upwards force of air resistance

Question 22

What are the different stages of skydiving

Answer 22

Initially he accelerates because of the force due to gravity. He then experiences the air resistance but this is not as great as his weight so he continues to accelerate. As his speed increases so does the air resistance until eventually R is equal to W. This speed is calling terminal velocity. When the parachute opens the upwards force of R is now bigger than W. This decreases his speed and as his speed decreases so does R. Eventually R decreases till its equal to W. Falls at steady speed.

Question 23

Formula for weight

Answer 23

Weight (N) = Mass (Kg) X Gravitational field strength (N/Kg)

Question 24

What do people consider when designing vehicles

What are racing cars designed like

Answer 24

To increase top speed and be more fuel efficient vehicles are designed to be streamline so as to reduce drag

They have a powerful engine to give a big driving force while being lightweight and very streamline. This combination means that they accelerate quickly and have to be going very fast before the drag force equals the driving force

Question 25

What is the force directly proportional to when you stretch an elastic object

Answer 25

The extension (the amount it is stretched by)

Question 26

What is it called when the extension exceeds a certain value

What happens

Answer 26

The limit of proportionality

The force and extension stop being directly proportional

Question 27

What is the formula for force

Answer 27

Force (N) = Spring constant (N/m) X Extension (m)