represent the motion of a train with constant speed and a car moving on a road with a variable speed graphically
Answers
Answer:
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.
Answer:
(i) Motion of your hands while running – Oscillatory motion.
Explanation: -
During running the hands move to and fro and as this motion gets repeated after certain time interval.
Therefore it is oscillatory motion.
(ii) Motion of a horse pulling a cart on a straight road – Straight line motion.
Explanation: -
As the horse cart is moving on a straight road. Therefore motion is along the straight line.
(iii) Motion of a child in a merry-go-round – Circular motion.
Explanation: -
Motion of the merry-go-round is circular. Therefore kids sitting inside it experiences the circular motion.
(iv) Motion of a child on a see-saw – Oscillatory motion.
Explanation: -
As the see-saw goes up and down continuously .Therefore it is oscillatory motion.
(v) Motion of the hammer of an electric bell – Oscillatory motion.
Explanation: -
When the hammer vibrates the bell it starts vibrating. It is an example of oscillatory motion.
(vi) Motion of a train on a Straight Bridge – Straight line motion.
Explanation: -
The train is moving on the straight bridge. It exhibits motion of a straight line.
Question2.
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.
Answer:
(i) The basic unit of time is second – Correct
Explanation: -
SI unit of time is second.
(ii) Every object moves with a constant speed - Not correct
Explanation: -
Speed of object is constant or variable.
(iii) Distances between two cities are measured in kilometres – Correct
Explanation: -
The distance between two cities is very large. And as a kilometre is a bigger unit therefore it is used
to measure the distance between two cities.
(iv) The time period of a given pendulum is not constant - Not correct
Explanation: -
The time period depends upon the length of the thread. Therefore it will be constant for a particular pendulum.
(v) The speed of a train is expressed in m/h - Not correct
Explanation: -
The speed of train is measured either in km/h or m/s.
Question 3.
A simple pendulum takes 32s to complete 20 oscillations. What is the time period of the pendulum?
Answer:
The time taken to complete one oscillation is known as time period of the pendulum.
Time Period = (Total time taken)/ (Number of Oscillations)
Given: - 20 oscillations taking 32s to complete.
Therefore 1 oscillation will take = (32)/ (20) sec = 1.6 second
Therefore 1.6s is the time period of the pendulum.
Question 4.
The distance between two stations is 240 km. A train takes 4 hours to cover this distance.
Calculate the speed of the train.
Answer:
Speed = (Distance travelled) / (Time)
= (240 km) / (4h)
=60 Km/h
Therefore the speed of the train is 60km/hr.
Answer:
(i) Oscillatory motion
While running, the hands move to and fro and repeat their motion after a given interval of time. Hence, it is an oscillatory motion.
(ii)Straight line
The horse is pulling a cart on a straight road. Therefore, it has a motion along a straight line.
(iii)Circular motion
Merry-go-round has a circular motion. Therefore, a child sitting inside it will also have a circular motion.
(iv) Oscillatory motion
The child on a see-saw goes up and down continuously. It oscillates up-down. Therefore, it is an oscillatory motion.
(v)Oscillatory motion
The hammer hits the electric bell and vibrates rapidly. Therefore, it is an oscillatory motion.
(vi) Straight line
The train is moving on a straight bridge. Therefore, it has a motion along a straight line.