Advertisements
Advertisements
प्रश्न
A bus running at a speed of 18 km/h is stopped in 2.5 seconds by applying brakes. Calculate the retardation produced.
Advertisements
उत्तर
We have to find the value of retardation. So,
Initial velocity,
`(u)` = 18 km/hr
= `"18(1000)"/3600` m/s
= 5 m/s
Final velocity, (v) = 0 m/s
Acceleration , `a = (v-u)/t`
Put the values in the above equation to get the value of acceleration
`a = (0-5)/2.5`
= `-2 "m/s"^2`
Thus, the retardation is 2 m/s2.
APPEARS IN
संबंधित प्रश्न
Fill in the following blank with suitable word :
Velocity is the rate of change of……………………… It is measured in.............. .
A motorcycle moving with a speed of 5 m/s is subjected to an acceleration of 0.2 m/s2. Calculate the speed of the motorcycle after 10 seconds, and the distance travelled in this time.
A body starting from rest travels with uniform acceleration. If it travels 100 m in 5 s, what is the value of acceleration ?
If a stone and a pencil are dropped simultaneously in vacuum from the top of a tower, then which of the two will reach the ground first? Give reason.
A car starting from rest acquires a velocity 180m s-1 in 0.05 h. Find the acceleration.
Write three equations of uniformly accelerated motion relating the initial velocity (u), final velocity (v), time (t), acceleration (a) and displacement (S).
When is the negative acceleration?
How can you find the following?
Acceleration from velocity – time graph.
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.
Two stones are thrown vertically upwards simultaneously with their initial velocities u1 and u2 respectively. Prove that the heights reached by them would be in the ratio of `"u"_1^2 : "u"_2^2` (Assume upward acceleration is –g and downward acceleration to be +g)
