In text Questions of page no 102
Q. No. 1 Distinguish between speed and velocity.
| Speed || |
Speed has only magnitude and no direction and hence it is a scalar quantity.
Velocity has magnitude as well as direction and hence it is a vector quantity.
Speed of a moving object cannot be zero.
Velocity of a moving object can be zero.
The rate of change of distance is known as speed.
The rate of change of displacement is known as velocity.
Q. No 2: Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?
Ans: The condition where the total distance covered by an object is the same as its displacement, then its average speed would be equal to its average velocity.
Q. No 3: What does the odometer of an automobile measure?
Ans:The odometer of an automobile measures the total distance covered by an automobile.
Q. No 4: What does the path of an object look like when it is in uniform motion?
Ans: When an object is in uniform motion then its path will be a straight line straight line.
Q. No 5: During an experiment, a signal from a spaceship reached the ground station in five minutes. What was the distance of the spaceship from the ground station? The signal travels at the speed of light, that is, 3 × 108 m s−1.
Ans: Time taken by the signal = 5 minute = 5 × 60 = 300 s
Speed of the signal = 3 × 108 m/s
We know that
Therefore Distance= Speed × Time
= 3 × 108 × 300
= 9 × 1010 m
So the distance of the spaceship from the ground station is 9 × 1010 m.