Advertisements
Advertisements
प्रश्न
An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 minutes 20 s?
Advertisements
उत्तर
Diameter, d = 200 m, r = `d/2` 100 m
Time for one round = 40 s
Distance travelled in 2 minutes and 20 s
(2 × 60 + 20 = 140 s)
= `140/40`
= 3.5 rounds
Distance travelled = Circumference of the circle × 3.5
= 2πr × 3.5
= `2 xx 22/7 xx 100 xx 3.5`
= 2200 m
Displacement after 3.5 rounds
= diameter of the track
= 200 m
APPEARS IN
संबंधित प्रश्न
Draw a velocity-time graph for a body moving with an initial velocity u and uniform acceleration a. Use this graph to find the distance travelled by the body in time t.
How can you find the following?
Displacement from velocity – time graph.
A motorbike running at 90 kmh−1, is slowed down to 54 kmh−1 by the application of brakes, over a distance of 40 m. If the brakes are applied with the same force, calculate
- total time in which bike comes to rest
- total distance travelled by bike.
A motor car slows down from 72 kmh−1 to 36 kmh−1 over a distance of 25 m. If the brakes are applied with the same force
calculate
- total time in which car comes to rest
- distance travelled by it.
A body is moving along a circular path of radius r. What will be the distance and displacement of the body when it completes:
Full revolution
A 50 m long train passes over a bridge at a speed of 30 km/h. If it takes 36 seconds to cross the bridge, calculate the length of the bridge.
The figure represents graphically the velocity of a car moving along a straight road over a period of 100 hours.
Calculate the distance travelled in the last 40 h.
An object covers a distance of S meters in t seconds as follows :
| S (meters) | 0 | 8 | 20 | 20 | 16 | 10 | 0 |
| t (Seconds) | 80 | 2 | 5 | 10 | 12 | 15 | 10 |
Plot a graph, taking t on X-axis and S on Y-axis. Determine the velocity of the object at time
(i) 6 s, and
(ii) 14 s.
The table below shows the distance travelled by two vehicles A and B during each second:
| Time (s) | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Distance travelled by A (m) | 0 | 20 | 80 | 180 | 240 | 300 | 360 | 420 |
| Distance travelled by B (m) | 0 | 10 | 40 | 90 | 160 | 250 | 360 | 490 |
Give the value of the velocity at which they are meeting
Give some examples for vector quantity.
