Class 7 Science
Motion and Time
Q.1
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.
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Q.2
Which of the following are not correct?
(i) The basic unit of time is second.
(ii) Every object moves with a constant speed.
(iii) Distances between two cities are measured in kilometres.
(iv) The time period of a given pendulum is not constant.
(v) The speed of a train is expressed in m/h.
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Q.3
A simple pendulum takes 32s to complete 20 oscillations. What is the time period of the pendulum?
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Q.4
The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train.
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Q.5
The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also.
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Q.6
Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school.
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Q.7
Show the shape of the distance-time graph for the motion in the following cases:
(i) A car moving with a constant speed.
(ii) A car parked on a side road.
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Q.8
Which of the following relations is correct?
(i) Speed = (Distance × Time)
(ii) Speed = (Distance /Time)
(iii) Speed = (Time/Distance)
(iv) Speed = (1/ (Distance x Time))
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Q.9
The basic unit of speed is:
(i) km/min (ii) m/min (iii) km/h (iv) m/s
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Q.10
A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:
(i) 100 km
(ii) 25 km
(iii) 15 km
(iv) 10km
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Q.11
Suppose the two photographs, shown in Fig (1) and Fig (2), had been taken at an interval of 10 seconds. If a distance of 100 metres is shown by 1 cm in these photographs, calculate the speed of the blue car.
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Q.12
Fig (3) shows the distance-time graph for the motion of two vehicles A and B. Which one of them is moving faster?
Fig (3):- Distance– time graph for the motion of two cars.
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Q.13
Which of the following distance-time graphs shows a truck moving with speed which is not constant?
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