Selina solutions concise physics class 7 icse Solutions for Chapter 2 motion

Q1) A car covers a distance of 300 km with an average speed of 60 km h-1. How much time does it take to cover the distance?

Q2) A train travels a distance of 300 km with an average speed of 60 km h-1. How much time does it take to cover the distance?

Q3) A boy travels with an average speed of 10 m s-1 for 20 min. How much distance does he travel ?

Q4) A boy walks a distance 30 m in 1 minute and another 30 min in 1.5 minutes. Describe the type of motion of the boy and find his average speed in m\ s^{-1}

Q5) A cyclist travels a distance of 1 km in the first hour, 0.5 km in the second hour and 0.3 km in the third hour.. Find the average speed of the cyclist in (i) km h^{-1} (ii) m s^{-1}

Q6) A car travels with speed 30 km h-1 for 30 minute and then with speed 40 km h-1 for one hour. Find :

(a) the total distance travelled by the car (b) the total time of travel, and (c) the average speed of car

Q7) On earth the weight of a body of mass 1.0 kg is 10 N. What will be the weight of a boy of mass 37 kg in (a) kgf (b) N ?

Q8) The weight of a body of mass 6.0 kg on the moon is 10 N. If a boy of mass 30 kg goes from earth to the moon surface,what will be his (a) mass, (b) weight ?

Q1) Write true or false for each statement

(a) two trains going in opposite directions with the same speed are at rest relative to each other.

(b) a ball is thrown vertically upwards. Its motion is uniform throughout.

(c) the motion of a train starting from one station and reaching at another station is non-uniform.

(d) A motion which repeats itself after a fixed interval of time is called periodic motion.

(e) a ball thrown by a boy from a roof top has oscillatory motion.

(f) mass has both magnitude and direction.

(g) weight always acts vertically downwards.

(h) mass varies from place to place but weight does not

Q2) Fill in the blanks

(a) two boys cycling on the road with the same speed are_– relative to each other.

(b) the motion in a _________ is rectilinear motion.

(c) one to and fro motion of a clock pendulum takes time = ______

(d) 36km\ h^{-1}= = _______

(e) total distance travelled = _______ total time taken

(f) the weight of a girl is 36 kgf. Her mass will be ________.

(g) the weight of a body is measured using a __________.

Q3) Match the following :

Q4) Select the correct alternative

(a) A book lying on a table is an example of

1. A body at rest

2. a body in motion

3. a body neither at rest nor motion

4. none of these

(b) the motion of a pendulum is ………………………………………………..

1. rotatory

2. oscillatory

3. curvilinear

4. rectilinear

(c) a car moving on a straight road is an example of ………………………………………………..

1. rotatory motion

2. rectilinear motion

3. oscillatory motion

4. periodic motion

(d) a ball falls down vertically. Its motion is ………………………………………………..

1. periodic

2. linear

3. circular

4. vibrator

(e) if a body covers equal distance in equal interval of time, the motion is said to be

1. uniform

2. non-uniform

3. oscillatory

4. rotatory

(f) a boy goes from his house to school by bus at a speed of 20 km h-1 and returns back through the same route at a speed of 30 km\ h^{-1}. the average speed of his journey is

1. 24 kmh1

2. 25 kmh1

3. 30 kmh1

4. 20 kmh1

(g) the earth attracts a body of mass 1 kg with a force of 10 N. the mass of a boy is 50 kg. His weight will be

1. 500 kg

2. 500 N

3. 50N

4. 5N

Q1) Explain the meaning of the terms rest and motion.

Q2) Comment on the statement ‘rest and motion are relative terms’. Give an example

Q3) Fill in the blanks using one of the words: at est,in motion.

(a) a person walking in a compartment of a stationary train is relative to the compartment of a moving train is relative to the other person sitting by his side and is relative to the platform.

(b) a person sitting in a compartment of a moving train is relative to the other person sitting by his side and is relative to the platform.

Q4) Name five different types of motion you know

Q5) What do you mean by translatory motion? Give one example

Q6) Explain the meanings of (i) rectilinear motion, and (ii) curvilinear motion. Give one example of each.

Q7) What is rotatory motion? Give two examples

Q8) What is meant by circular motion? give one example.

Q9) How does a rotatory motion differ from the circular motion?

Q10) Explain oscillatory motion by giving one example.

Q11) What is vibratory motion? Give one example.

Q12) Differentiate between periodic and non-periodic motions by giving an example of each

Q13) What is random motion? Give one example.

Q14) Name the types/types of motion being performed by each of the following:

(a) vehicle on a straight road (b) blades of an electric fan in motion (c) pendulum of a wall clock (d) smoke particles from chimney (e) hands of a clock (f) earth around the sun (g) a spinning top

Q15) Give two examples to illustrate that a body can have two or more types of motion simultaneously.

Q16) State the types of motion of the following

(a) the needle of a sewing machine (b) the wheel of a bicycle (c) the drill machine (d) the carpenter’s saw

Q17) Distinguish between uniform and non- uniform, giving an example of each

Q18) How do you determine the average speed of a body in non-uniform motion?

Q19) Define the term weight and state its S.I. unit.

Q20) How are the units of weight, kgf and newton related?

Q21) State three differences between mass and weight.

Q22) Which quantity: mass or weight is always directed vertically downwards.

Q23) State which of the quantities, mass or weight is always directed vertically downwards.