Advertisements
Advertisements
प्रश्न
When brakes are applied to a bus, retardation produced is 25 cm s-2 and the bus takes 20 s to stop. Calculate -
- The initial velocity of the bus
- The distance travelled by bus during this time.
Advertisements
उत्तर
Final velocity (v) = 0
retardation = -25 cm/s2
Expressing it in m s-2
25 cm s-2 = `25/100` m s-2
Hence, - a = - 0.25 m s-2
Time taken (t)= 20 s
(i) Let 'u' be the initial velocity.
Using the first equation of motion,
v = u + at
We get,
u = v - at
u = 0 - (- 0.25)(20)
u = 5 m s-1
(ii) Let 's' be the distance travelled.
Using the third equation of motion,
v2 - u2 = 2as
We get,
∴ (0) 2 - (5)2 = 2 (-0.25) (s)
∴ 0 - 25 = - 0.5 × s
∴ - 25 = - 0.5 s
∴ `(- 25)/(- 0.5)` = s
∴ s = 50 m.
APPEARS IN
संबंधित प्रश्न
Is displacement a scalar quantity?
In which of the following cases of motion, the distance moved and the magnitude of displacement are equal?
Differentiate between distance and displacement.
A ball moves on a smooth floor in a straight line with uniform velocity 10 m s-1 for 6 s. At t = 6 s, the ball hits a wall and comes back along the same line to the starting point with the same speed. Draw the velocity-time graph and use it to find the total distance travelled by the ball and its displacement.
Can you suggest the kind of motion of a body from the following distance – time graph?
Calculate the distance and displacement in the following case:
Which of the following figures represent uniform motion of a moving object correctly?
Match the following.
| 1. | Displacement | Knot |
| 2. | Light travelling through vacuum | Geometric centre |
| 3. | Speed of ship | Metre |
| 4. | Centre of gravity of geometrical shaped objects | Larger base area |
| 5. | Stability | Uniform velocity |
Give one example where the displacement is zero but the distance travelled is not zero.
The displacement covered by the second hand of radius V in a clock after one revolution is ______.
