Download P2.3 Forces

P2 Forcees and Motion Revision Sheet
1. What is a resultant force? [1]
A single force which is the result of 2 or
more forces acting on an object.
2. What is the unit of force? [1]
Newton
3. What is the equation relating force, mass
and acceleration? [1]
F=ma
4. When an object moves through air or
water they experience this force [1]
Drag force
5. Define acceleration [1]
The rate at which velocity changes.
6. What is a reaction force? [1]
7. What are the forces acting on a book on a
table?
8. What law states extension of the material
is proportional to the force applied? [1]
The surface an object rests on exerts
an equal and opposite force, called the
reaction force
 Weight (downwards)
 Reaction (upwards)
Hooke’s Law
When an object recovers its original
shape after a force has been applied
 Thrust
10.What are the horizontal forces acting on an
 friction
accelerating car? [3]
 in opposite directions
11. What are the vertical forces acting on a
 Weight (downwards)
boat? [2]
 Upthrust or buoyancy (upwards)
12. If there is a resultant force on a moving
object will it accelerate or travel at a steady Accelerate
speed? [1]
 Force on the object
13.To change the acceleration of an object you
would need to change… [2]
 Mass of the object
9. What does elastic mean? [1]
14. The name given to energy stored in a
stretched elastic band [1]
Elastic potential energy
15. When 2 objects interact, the forces they
exert on each other are said to be… [1]
Equal and opposite
16. What is the name of the force that causes
heating effects? [1]
Friction
17. What is the unit of mass? [1]
Kilograms
18. Name the letters in this equation
F=ma
F = force (N)
a = acceleration (m/s2)
m = mass (kg)
19. If an object has an acceleration of 10 m/s2
and a mass of 2 kg what is the size of the
force?
20.If an object has an acceleration of 5 m/s2
and a mass of 20 kg what is the size of the
force?
21.If a 20N force is applied to a mass of 2 kg
what is the acceleration?
22.If a 15N force is applied to a mass of 3 kg
what is the acceleration?
23. What is the mass of a toy car if it has an
acceleration of 2 m/s2 when a force of 8 N
is applied?
24. Name the letters in F = ke
25.If a spring with a spring constant of
10 N/m, stretches 0.5 m, what was the
force applied?
26. If a spring with a spring constant of
5 N/m, stretches 2 m, what was the force
applied?
27.If a spring with a spring constant of
5 N/m, stretches 20 cm, what was the force
applied?
28.If a force of 10N is applied to a spring with
a spring constant of 5 N/m, how much does
the spring stretch?
29.If a force of 50N is applied to a spring which
stretches 2 m, what is the size of the spring
constant?
F = force (N)
k = spring constant (N/m)
e = extension (m)
motion
1. How is velocity different to speed? [1]
2. How can you calculate speed from a
distance-time graph? [2]
Velocity is speed in a certain direction
 From the gradient
 because speed = distance /
time
3. Define Acceleration [1]
The rate at which velocity changes.
4. How can you calculate acceleration from a
velocity-time graph? [1]
From the gradient because;
acceleration = change in velocity /
time
5. What is braking distance? [1]
The distance a vehicle travels whilst
the brakes have been applied.
6. What is thinking distance? [1]
The distance a vehicle travels whilst
the driver is thinking about braking.
7. What is stopping distance? [2]
 The total distance a vehicle
travels to come to a stop.
 It is the sum of the breaking
and thinking distances
8. What is terminal velocity? [1]
This is a steady speed caused when
the forces are balanced. Example is a
sky diver
9. List 3 ways of increasing braking distance [3]
 Wet or icy road
 Worn brakes
 Worn tyres
10. List 3 ways of increasing thinking distance
[3]
 Drugs or alcohol
 Tired
 Using a mobile phone
11. Why does a sky diver have a large
parachute? [3]
 To increase the surface area
 To increase the drag force
 To decrease the acceleration
12. What is the unit of acceleration? [1]
m/s2
13. What is the unit of velocity? [1]
m/s
14. Equation to calculate speed [1]
Speed = distance / time
15. If a car travels 500m in 20 seconds, what is
its speed? [1]
16.If a bike travels 200m in 2 seconds, what is
its speed? [1]
17. If a rabbit hops 30m at a speed of 2 m/s,
how long will it take? [1]
18.If a plane travels 40km at a speed of 50 m/s,
how long will it take? [1]
19. If a car travels for 300 seconds at a speed of
15 m/s, how far has it travelled? [1]
20.If a car travels for 40 minutes at a speed of
15 m/s, how far has it travelled? [1]
21. Equation to calculate acceleration [1]
a =(v – u) / t
22. If a car starts from rest (starting velocity is 0
m/s) and accelerates to a velocity of 100 m/s
in 20 seconds, what is its acceleration? [1]
23. If a car starts to accelerate from a velocity
of 5 m/s to a velocity of 25 m/s in 20
seconds, what is its acceleration? [1]
24.If a boat starts to accelerate from a velocity
of 20 m/s to a velocity of 30 m/s in 5
seconds, what is its acceleration? [1]
25. If a train starts from rest and accelerates to
a velocity of 80 m/s with an acceleration of
20 m/s/s, how long did it accelerate for? [1]
26. If a bus starts from rest and accelerates to a
velocity of 10 m/s with an acceleration of 2
m/s/s, how long did it accelerate for? [1]
27.If a bike starts from rest and travels for 10
seconds with an acceleration of 2 m/s/s,
what is the final velocity? [1]
28.If a car starts from rest and travels for 5
seconds with an acceleration of 3 m/s/s,
what is the final velocity? [1]
29. Equation to calculate weight[1]
30. If a boy has a mass of 50kg, what is his
weight? [1]
W=m g