Science on the Road (Physical World)

Question 1

What is speed?

Answer 1

Distance an object has traveled in a given time. Speed is measured in many units. E.g m/s, km/h.

Question 2

How is the average speed calculated?

Answer 2

The total distance traveled by the total time taken.

D/S

Question 3

What is velocity?

Answer 3

The speed of something in a given direction. e.g 20/km East

Question 4

Who would be interested in velocity?

Answer 4

Pilots, ships, scientists and sports people all use velocity, as they are in interested in movements in straight lines.

For example, if a football player is shooting for a goal, he will alter the path of the direction the ball should be kicked if there is a cross wind blowing.

Question 5

What is acceleration?

Answer 5

Acceleration is an increase in speed.
It is the way that an object’s velocity changes over time.

Like velocity and displacement, acceleration is concerned with both the direction and time the travel takes.

Question 6

How do you calculate the average acceleration?

Answer 6

Acceleration - change in speed (m/s) / time taken (s)

Question 7

What is deceleration?

Answer 7

Deceleration is decreasing speed. If the answer is negative when calculating acceleration, then it’s a decreased acceleration (deceleration)

Question 8

What can slopes indicate on a speed-time graph?

Answer 8

•A slope on a speed-time graph shows either acceleration (increasing speed) or deceleration (decreasing speed)

Question 9

How can acceleration or deceleration be shown on a ticker timer?

Answer 9

Acceleration or deceleration can be shown on a ticker-tape where the spaces between the
dots increase

Question 10

What is the relationship between speed, distance and time?

Answer 10

Speed = Distance/time
Distance= speed x time
Time = Distance/speed

Question 11

What are forces?

Answer 11

A push, pull or twist that causes an object to accelerate, decelerate, change direction or change shape

Question 12

What unit is force measured in?

Answer 12

Newton (N). One Newtown is the force which causes a mass of 1 kg to accelerate 1m/s/s.

Question 13

How can force be measured?

Answer 13

Using a spring balance. The larger the force, the more the spring extends with the force level

Question 14

On a car, what forces are acting on it?

Answer 14

There are 4.

thrust – the force applied to the wheels by the road

weight – the force applied by Earth’s gravity

resistance forces (drag) – friction and air resistance

(upwards push of the road – a reaction force equal to weight

Question 15

How is the size and direction of an arrow related to force?

Answer 15

We represent vectors with arrows - the size of the arrow shows the relative magnitude of the force, while the direction of the arrow shows in which direction the force is acting.

Question 16

How is an object stationary? (net force)

Answer 16

The forces cancel each other out.

For example, If there is a force acting on an object and it is 5 Newton to the left, and at the same time there is a 5 N force to the right acting on that same object, this would be like subtracting 5 to the right. 5 - 5 = 0, so we have zero net force.

Question 17

What happens if there is two forces in opposing directions?

Answer 17

Whatever side with a force greater, is where the net force will be.

For example we have 5 N to the right and 15 N to the left. 15 - 5 = 10, and since the greater magnitude force is acting to the left, that’s where our net force is, too. So in this case, the net force is 10 N to the left.

Question 18

How many Newton’s Laws are there?

Answer 18

Three

Question 19

What is Newton’s first law?

Answer 19

Any object will remain at rest or will not change it’s speed unless an unbalanced force is acted upon it.

Question 20

What is inertia?

Answer 20

Inertia is an object’s resistance to change in motion, depending on its mass. The greater the mass the greater the inertia.

Question 21

What is an example of inertia?

Answer 21

Inertia is what makes you appear to go forward when a car suddenly brakes (your
body wants to continue going forward at that speed)

Inertia is what makes your head appear to go back if you are hit from behind by
another car (your head wants to stay still)

Question 22

What is Newton’s second law?

Answer 22

The mass of an object affects the way that it moves when acted upon by one or more forces. (Force = mass x acceleration)

A force is necessary to accelerate an object

• The more force that is applied, the more the acceleration.
• The heavier an object is, the more force is needed to accelerate it

Question 23

What is Newton’s third law?

Answer 23

For every action there’s an equal and opposite reaction.

Question 24

What are some example of Newton’s Third Law of Motion.

Answer 24

E.g. Swimming. Pushing back with your hand against the water results in a forward
motion
- E.g. Rockets. The matter thrown out the back of the rocket (action force) results in
forward motion (reaction force)
- E.g. Walking. Pushing back with your foot on the ground (action force) results in
forward motion (reaction force)

Question 25

What is mass?

Answer 25

Amount of material in an object (g, kg).

Related to the number of atoms an object has.
Does not change.

Question 26

What is weight?

Answer 26

the force of gravity on an object (Newtons)

The force with which the Earth or some other object attracts a mass

-Depends on where you are (you weigh less on the Moon than on Earth, although your mass is the same)