Work
Power
Laws of Motion
Speed
Friction
100
This is the amount of force applied over a certain distance or Blank = Force x distance
What is Work
100
This the rate at which work is done or Blank = Work/time
What is Power
100
Scientist that put together the laws of motion
Who is Isaac Newton?
100
A boy walks at a speed of 4 kmph. How much time does he take to walk a distance of 20 km?
Time = Distance / speed = 20/4 = 5 hours.
100
What is friction?
Friction is a force, the resistance of motion when one object rubs against another. Whenever two objects rub against each other, they cause friction. Friction works against the motion and acts in the opposite direction. The amount of friction depends on the materials from which the two surfaces are made.
200
This is the unit that Work is measured in.
What is a Joule (J)/What are Joules (J)
200
This is the unit that power is measured in blank.
What is Watts
200
Which states thatis more mass needs more force?
2nd law of motion
200
A cyclist covers a distance of 15 km in 2 hours. Calculate his speed (do not round)
Speed = Distance/time
= 15/2
= 7.5 km per hour.
200
Ways to increase friction
Rough the surface – more hills and valleys and there are not are deeper. Replace rolling with sliding More force pushing together – The hills and valleys are pushed together harder so the hills and valleys are in closer contact.
300
What is the formula for finding the amount of work done on an object?
Work = Force x distance
300
Formula of power
300
THis pictures shows which law of motion
Second law of motion
300
If a person drives his car in the speed 50 km per hour, how far can he cover in 2.5 hours?
Solution :
Given : Speed is 50 km per hour. So, the distance covered in 1 hour is = 50 km. Then, the distance covered in 2.5 hours is = 2.5 ⋅ 50 km
= 125 km
So, the person can cover 125 miles of distance in 2.5 hours.
300
Ways to reduce friction
Smooth the surface – less hills and valleys and there are not as deep. Replace sliding with rolling (Use Wheels) Add a lubricant like oil, wax, or grease – Fills in the hills and valleys. Less force pushing together – The hills and valleys are not pushed together as hard so they have less contact.
400
A 10 kg object experiences a horizontal force which causes it to accelerate at 5 m/s2?
The magnitude of the force is given by F = ma = (10)(5) = 50 N.
400
How much power is required to do 200 joules of work in 4 seconds?
Power =
200/4
Power = 50 watt
400
The boy caught a ball. Which law of motion is this?
First law of motion
400
A person travels at a speed of 60 km per hour. How far will he travel in 4.5 hours?
Solution :
Given : Speed is 60 km per hour. The distance covered in 1 hour is = 60 km
Then, the distance covered in 4.5 hours is
= 4.5 ⋅ 60 km
= 270 km
So, the person will travel 270 km distance in 4.5 hours.
400
Types of friction
1. Sliding
2. Fluid
3. Rolling
4. Static
500
10 kg weight is suspended in the air by a strong cable. How much work is done, per unit time, in suspending the weight?
No movement, therefore, it is not work.
500
If I do 2000 Joules of work in 5 seconds, I produce this amount of power.
What is 400 watts.
500
This picture shows us which law of motion
Third law of motion
500
Calculate the average speed of a lion that runs 45 meters in 5 seconds .
Speed = d/t
Speed = 45/5
d = 9 meters per second.
You could also write d = 9 m/s.
500
Friction in your everyday life
Answer may vary