Advertisements
Advertisements
प्रश्न
A bus was moving with a speed of 54 km/h. On applying brakes it stopped in 8 seconds. Calculate the acceleration.
Advertisements
उत्तर
(b) We have to find the value of uniform acceleration. So, Initial velocity
(u) = 54 km/hr
= `"54(1000)"/3600` m/s
= 15 m/s
Final velocity (v) = 0 m/s
Time taken(t) = 8 s
So acceleration, `a = (v-u)/t`
Put the values in the above equation to get the value of acceleration
`a = (0-15)/8`
= -`1.875 "m/s"^2`
APPEARS IN
संबंधित प्रश्न
What term is used to denote the change of velocity with time ?
Derive the formula : v = u + at, where the symbols have usual meanings.
The slope of a speed-time graph gives:
The figure shows the displacement - time graph for four bodies A, B C and D. In each case state what information do you get about the acceleration (zero, positive or negative).
Multiple choice Question. Select the correct option.
A body dropped from the top of a tower reaches the ground in 4s. Height of the tower is
How can you find the following?
Velocity from acceleration – time graph.
Can you suggest a real-life example about the motion of a body from the following velocity – time graph?
A packet is dropped from a stationary helicopter, hovering at a height ‘h’ from ground level, reaches the ground in 12s. Calculate
- the value of h
- final velocity of packet on reaching the ground. (Take g = 9.8 ms−2)
A girl walks along a straight path to drop a letter in the letterbox and comes back to her initial position. Her displacement–time graph is shown in Fig.8.4. Plot a velocity-time graph for the same.
An object starting from rest travels 20 m in the first 2 s and 160 m in the next 4 s. What will be the velocity after 7 s from the start?
