The attraction between the Earth and any object is gravity, and force is measured in newtons, so this Grade 8 sheet begins with the pulled-toward-Earth force. Pressure is recorded as force ÷ area, and friction is given as a contact force.
Key Takeaways
The force of attraction between the Earth and any object is gravity (Q1).
The SI unit of force is the newton (Q2).
Pressure equals force ÷ area (Q3).
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.The force of attraction between the Earth and any object is called:
(a) Friction(b) Gravity(c) Magnetic force(d) Muscular force
2.The SI unit of force is:
(a) Pascal(b) Joule(c) Newton(d) Watt
3.Pressure is defined as:
(a) Force × Area(b) Force ÷ Area(c) Area ÷ Force(d) Force + Area
4.Which force stops a moving bicycle when its brakes are applied?
(a) Friction(b) Gravity(c) Magnetic force(d) Muscular force
5.The pressure exerted by a liquid at a point increases with its:
(a) Volume(b) Mass(c) Depth(d) Surface area
6.A sharp knife cuts better because the area of contact is:
(a) Large(b) Small(c) Zero(d) Infinite
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.Define force. Give two examples of contact forces and two examples of non-contact forces.
8.Why does a balloon filled with air burst when pricked with a sharp needle?
9.What is atmospheric pressure? Name the instrument used to measure it.
10.Why do school bags have wide, flat straps?
11.State the two factors on which the pressure exerted by a force on a surface depends.
12.Why does a camel have broad flat feet?
13.What is buoyancy? Why do some objects float in water while others sink?
14.Why are railway tracks laid on thick wooden or concrete sleepers?
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A force of 100 N is applied uniformly on an area of 4 m². Calculate the pressure exerted.
16.A brick weighing 60 N is placed on a surface. If its contact area is 0.5 m², find the pressure it exerts.
17.A woman weighing 600 N stands on one foot of area 0.02 m². Calculate the pressure exerted by her foot on the ground.
18.A force of 150 N produces a pressure of 30 Pa. Calculate the area on which the force acts.
19.The tip of a nail has an area of 0.0001 m². If a force of 20 N is applied on it, find the pressure produced.
20.A force of 500 N is applied on a surface of area 2.5 m². Find the pressure. Also, find the new pressure if the area is doubled.
Answer Key
1. b) Gravity
2. c) Newton
3. b) Force ÷ Area
4. a) Friction
5. c) Depth
6. b) Small
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End of Worksheet
People Also Ask
What is the force of attraction between the Earth and any object?
Gravity, option (b) in this worksheet (Q1).
What is the SI unit of force?
The newton, option (c) in this worksheet (Q2).
How is pressure calculated?
Force ÷ area, option (b) in this worksheet (Q3).
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