Question

stion
1. Distinguish between speed and
velocity.
2. Under what condition(s) is the
magnitude of average velocity of
an object equal to its average
speed?
3. What does the odometer of an
automobile measure?
4. What does the path of an object
look like when it is in uniform
motion?
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 x 108
ms!​

Answer 1

1. Speed

• Speed is the distance travelled by an object in a unit time.It has no direction.
• Speed is a scalar quantity
• Speed =distance travelled/Time taken
• The speed of an object can never be negative.At most it can become zero.This is because distance travelled can never be negative.

Velocity

• Velocity is the displacement of an object per unit time in a particular direction.
• Velocity is a vector quantity.
• Velocity =displacement/time.
• The velocity of an object can be negative ,positive or equal to zero.This is because displacement can take any of these 3 values.

2.Average speed

=Total distance/Total time taken

Average velocity

=Displacement/Total time taken

If the total distance covered by an object is the same as its displacement then its average speed would be equal to its average velocity.

3. Distance.

4.Straight line.

5. Time taken by the signal to reach the ground station from the spaceship

=5min=5×60=300sec

Speed of the signal=3×10^8m/s

Speed=Distance travelled/Time taken

Distance=speed×time

=3×10^8×300=9×10^10m

Hence,the distance of the spaceship from the ground station=9×10^10m