Speed and Velocity - UNSOLVED PRACTICE SET

Q7. Define speed and velocity. Why is speed a scalar quantity while velocity is a vector quantity?

Q8. What is meant by 'average speed'? Write the formula. A cyclist covers 12 km in 40 minutes — calculate his average speed in m/s.

Q9. Can the average velocity of an object be zero even when its average speed is not zero? Explain with an example.

Q10. Distinguish between uniform speed and variable speed with one example each. Which is more common in real life and why?

Q11. A KSRTC bus travels from Bangalore to Mysore (140 km) in 2.5 hours.
(a) Calculate its average speed in km/h.
(b) Is this the actual speed at every moment? Explain what 'average' means here.

Q12. Write the formula for average velocity. A car goes 60 km East in 1 hour, then 60 km West in 2 hours. Calculate
 (a) average speed and
(b) average velocity for the whole journey.

Q13. A school bus leaves school at 2:00 PM and reaches the first student's home (3 km North) at 2:10 PM. It then travels to the second student's home (4 km East of the first home) arriving at 2:25 PM.
(a) Calculate the speed for each leg of the journey.
(b) Calculate the total distance and total time.
(c) Calculate the overall average speed.
(d) Calculate the magnitude of the net displacement from school.
(e) Calculate the average velocity (magnitude) for the full journey. 

Q14. Explain with examples the difference between instantaneous speed and average speed.
(a) Define both terms.
(b) Why does a car's speedometer show instantaneous speed and not average speed?
(c) A cyclist travels 5 km in the first 20 minutes, 3 km in the next 10 minutes, and 7 km in the last 30 minutes. Calculate the average speed for the entire journey.
(d) Was the speed the same throughout? Justify.

Q15. Riya drives her scooty in a city. She drives 4 km North in 10 minutes, then turns and drives 3 km East in 6 minutes, then turns and drives 4 km South in 10 minutes.
(a) Calculate the average speed for the full journey.
(b) Find the total displacement from start.
(c) Calculate the average velocity.
(d) Why is the average velocity less than the average speed in this case?

Q16. Light travels at 3 × 10⁸ m/s.
(a) How long does light take to travel from the Sun to Earth (distance = 1.5 × 10¹¹ m)? Give your answer in minutes.
(b) How far does light travel in 1 nanosecond (1 ns = 10⁻⁹ s)? (c) Sound travels at 340 m/s in air. How much longer does sound take than light to travel 1 km?

Q17. An auto-rickshaw in Jaipur covers the first 5 km in 15 minutes, stops at a signal for 2 minutes, then covers the next 4 km in 8 minutes.
(a) Calculate the average speed (in m/s) for each moving segment.
(b) Calculate the average speed for the entire trip including the stop.
(c) What was the average velocity if the final point is 7 km from the start in a straight line?

Q18. A cheetah spots a deer 200 m away and accelerates to a top speed of 30 m/s (treat this as its constant speed during the chase). The deer runs at a constant 20 m/s.
(a) At what rate does the cheetah close the gap (relative speed)?
 (b) How long will it take the cheetah to cover the 200 m gap?
(c) How far will each animal have run by the time the cheetah catches up?