CBSE Class 8 Science Friction Worksheet Set 01

Question. Shown here is an object whose weight is found out using a spring balance, but with the object dipped in water to different extents as shown. In which of these will it record minimum weight?

Answer : C

Question. Shown below are drill bits which are fixed to a drill to make holes in a wall. All the bits shown are for making holes of the same diameter. With which one will it be EASIEST to drill the hole?

d

Question. Ice sinks in methanol, but floats on water. From this we can conclude:
(a) The density of ice in methanol must be different from that in water.
(b) The density of water must be less than the density of methanol.
(c) The density of ice must be greater than the density of water.
(d) The density of methanol must be less than the density of water.

Answer : D

Question. Here is the picture of an aircraft, with the forces working on it shown. Identify the force that corresponds to the question mark.

(a) Buoyancy
(b) Atmospheric pressure
(c) Gravity
(d) Density

Answer : C

Question. An ant and a stone are on a circular disc, which is rotating at constant speed. The stone is fixed to the disc. The ant is moving along the rim in the opposite direction and with the same speed as that of the disc.
Which of these shows the position of the ant and the stone after the disc completes 3/4th of a revolution?

Answer : B

Question. A wet cloth was placed on a balance and left for several days. The change in its mass is shown in the graph here:
What was the mass of WATER in the cloth at the start of the experiment?

(a) 60 g
(b) 36 g
(c) 24 g
(d) 10 g

Answer : B

Question. A vessel containing a liquid 'L' is balanced by a solid 'S' as shown below. Now, two identical pieces of cork (which float on the liquid) are placed gently, one on the solid and one in the liquid. What will happen to the balance? 

(a) The pan carrying the liquid 'L' will go down.
(b) The pan carrying the solid 'S' will go down.
(c) There will be no change in the balance.
(d) Depending on the density of 'S', either pan may go down.

Answer : C

Question. There is a glass of water in a cup holder in a car which is undisturbed. The car now starts moving up a steep hill at a STEADY SPEED. Which of these could be the shape of the water surface?

Answer : C

Question. The diagrams show different trials Abdul carried out with carts having different-sized wheels. He started them from different heights and the blocks he put in them were of equal mass. He wants to test this idea: The heavier a cart, the greater its speed at the bottom of a ramp. Which three trials should he compare? 

(a) G, T, and X
(b) O, T, and Z
(c) R, U, and Z
(d) S, T, and U

Answer : D

Question. Four students saw a stone and a sheet of paper being dropped from the same height at the same instant. The stone landed on the ground much before the paper did. The person who conducted the experiment asked them as to the reason why the stone fell first. The reasons given were as follows:
Nitya: The stone falls faster as a heavier object always falls faster than a lighter one.
Kenneth: The stone falls faster as there is no force acting on it.
Priya: The paper falls more slowly as it has less gravitation force acting on it.
Ruchira: The paper falls more slowly as there is more air resistance acting on it.
Which of them is correct?
(a) Nitya
(b) Kenneth
(c) Priya
(d) Ruchira

Answer : D

Question. On a windless day, two identical balls P and Q are dropped from the top and the middle of a tower at exactly the same time as shown. Which will be more: the time taken by P to reach the middle of the tower, or the time taken by Q to reach the ground

(a) They will be the same.
(b) The time taken by P will be more.
(c) The time taken by Q will be more.
(d) It depends on the weight of the balls.

Answer : A

Question. A man is standing on a weighing scale in a stationary lift, which is on the 10th floor. The scale shows 80 kg. The lift now starts moving down and stops only on the ground floor. Which of these could be the different readings shown by the scale during the motion?
(a) 80kg - 77 kg - 74kg - 77kg - 80kg
(b) 80kg - 77 kg - 80kg - 83kg - 80kg
(c) 80kg - 83 kg - 80kg - 77kg - 80kg
(d) 80kg - 80 kg - 80kg - 80kg - 80kg

Answer : B

Question. Bhargav rolled a ball on a floor. The ball stopped moving by itself after a while and came to rest. The ball came to rest because______________.
(a) somebody stopped the ball
(b) Of the force of friction
(c) Bhargav rolled the ball slowly
(d) The floor was not smooth

Answer : B

Question. Rajesh was walking along the footpath. He stepped on a banana skin and slipped. Rajesh slipped because
(a) He was careless.
(b) He exerted a lot of force on the banana skin.
(c) The banana skin reduced the friction between his shoes and the foot path.
(d) His shoes were torn.

Answer : C

Question. If you wanted to bounce a ball off a smooth wall to hit the wooden block, along which path (A, B, C or D) should you roll the ball?

(a) A
(b) B
(c) C
(d) D

Answer : D
 

              Questions

              Very Short Answer

Q1)       Define lubricants?

Q2)       What is spring balance?

Q3)       What is drag?

Q4)       How friction is caused?

Q5)       How friction is reduced in many machines?

             Short Answer

 Q6)       What are the advantages of the friction?

Q7)       Why it is difficult to walk on a smooth and wet surface?

Q8)       What do you mean by fluid friction?

Q9)       How wheel reduce friction?

Q10)     Why rubbing of our palm makes us feel warm?

             Long Answer

 Q11)     Explain the methods of increasing friction?

Q12)     Write short note on friction?

Q13)     Explain the methods of reducing friction?

Q14)     Explain the types of the friction?

Q15)     State the difference between sliding friction and rolling friction?