Force and Types of Force Q & A
Q.1. Choose the term and fill in the blanks:
(a) Force has to be applied to change the direction of a moving object.
(moving, direction, force)
(b) When an elephant drags a wooden log over the land, the forces that are applied on the log are muscular force , gravitational force and frictional force .
(muscular force, mechanical force, gravitational force, frictional force)
(c) A ball was set rolling on a large table. If its motion is to be changed, a force will have to be applied on it.
(force, motion, gravitation)
(d) The force of friction always acts against the motion.
(along, against)
Q.2. Match the following:
Column ‘A’ | Answer |
1. An ox pulling a cart | c. Muscular force |
2. Lifting heavy iron object with a crane | a. Magnetic force |
3. Weighing with a spring balance | d. Gravitational force |
4. Applying brakes to a bicycle | e. Frictional force |
5. Picking up pieces of paper with a plastic scale | b. Electrostatic force |
Q.3. One or more forces are acting in the following examples. Name them.
(a) An object falling from a tall building ….
Ans: Gravitational force.
(b) An aeroplane flying in the sky ….
Ans: Mechanical force.
(c) Sqeezing sugarcane juice with a squeezer ….
Ans: Muscular or mechanical force.
(d) Winnowing foodgrain …………. .
Ans: Muscular force, gravitational force.
Q.4. Explain in your own words giving one example each.
Muscular force, gravitational force, mechanical force, electrostatic force, the force of friction and magnetic force.
Q.5. Why?
(a) Machines are oiled from time to time.
Ans: Machines are oiled from time to time to reduce the friction between the parts of machines. It will help efficient working of machines.
(b) An object thrown upwards comes down after reaching a point.
Ans: An object thrown upwards comes down after reaching a point because it is pulled by the gravitational force of the earth.
(c) Powder is sprinkled on a carrom board.
Ans: When powder is sprinkled on a carrom board then friction between the coin and the board decreases so that the coin can be pocketed easily.
(d) The ramp at a railway station has a rough surface.
Ans: The rough surface of the ramp increases the friction between feet and the surface. It helps us to walk on the ramp without skidding or falling.
Q.6. In what way are we different?
(a) Muscular force and Mechanical force.
Ans: The force applied with the help of muscles is called muscular force and it is created by our muscles. The force applied by means of machine is called mechanical force and it is created by electricity or fuel or muscular force.
(b) The force of friction and gravitational force.
Ans: When two surfaces rub against each other, the force of friction comes into force and it comes to act between two surfaces.The force applied by the earth to pull an object towards itself, is called a gravitational force and it exists between two objects or an object and the earth.
Q.7. Write answers to the following questions in your own words.
(a) What are the things that can be done by applying force?
Ans: By applying force:
(1) We can set an object in motion.
(2) We can stop a moving object.
(3) We can change the speed or direction or both of a moving object.
(4) We can change the shape of an object.
(b) What is meant by weight?
Ans:The gravitational force acting on an object is called its weight.
(c) Which machines run on muscular force?
Ans: The machines that run on muscular force are:
- Bicycle
- Hand cart
- Boat
- Auto-rickshaw
- Stretching of a spring
- Ball pen
- Vegetable chopper
- Sharpener
- Pulley
- Fruit peeler
Q.8. Solve the following crossword puzzle.
Down:
(1) Muscular force is applied to push a scooter that has failed.
(2) Magnetic force can be used to pick up scattered pins.
Across:
(3) A magnet pulls iron nails towards itself.
(4) Machenical force is used when farm is ploughed with a tractor.
(5) It is due to the force of gravity that raindrops fall to the ground.