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प्रश्न
What do you mean by constant acceleration?
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उत्तर
A body is said to have constant acceleration, if it travels is a straight line and its velocity increases or decreases by equal magnitude in equal intervals of time.
Ex: the motion of a freely falling body.
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संबंधित प्रश्न
Define the term acceleration due to gravity. State its average value.
The unit of retardation is ____________
Figure given below shows a velocity-time graph for a car starting from rest. The graph has three parts AB, BC and CD.
Which part of graph shows motion with uniform
(a) velocity (b) acceleration (c) retardation ?
A space craft flying in a straight course with velocity of 75 km s-1 fires its rocket motors for 6.0 s. At the end of this time its speed is 120 km s-1 in the same direction.
Find
(i) The space craft's average acceleration while the motors were firing
(ii) The distance travelled by the space craft in the first 10 s after the rocket motors were started, the motors being in action for only 6 s.
A car travels with uniform velocity of 25 m s-1 for 5 s. The brakes are then applied and the car is uniformly retarded and comes to rest in further 10 s. Find:
- The distance which the car travels before the brakes are applied,
- Retardation and
- The distance travelled by car after applying the brakes.
A vehicle is accelerating on a straight road. Its velocity at any instant is 30 km/h. After 2 s, it is 33.6 km/h, and after further 2 s, it is 37.2 km/h. Find the acceleration of the vehicle in m s-2. Is the acceleration uniform?
An aeroplane lands at 216 kmh−1 and stops after covering a runway of 2 m. Calculate the acceleration and the time, in which it comes to rest.
A truck running at 90 kmh−1, is brought to rest over a distance of 25 m. Calculate the retardation and time for which brakes are applied.
A motor bike running at 5 ms−1, picks up a velocity of 30 ms−1 in 5s. Calculate
- acceleration
- distance covered during acceleration.
The acceleration of a moving body is constant in magnitude and direction. Must the path of the body be a straight line?
If not, given an example.
A body falls towards the earth. Does it have positive or negative acceleration?
Write the SI unit of retardation.
A car traveling at 60 km/h, stops on applying brakes in 10 seconds. What is its acceleration?
Sketch the shape of the velocity-time graph for a body moving with:
Uniform acceleration.
A car starts from rest and it is travelling with a velocity of 20 m/s in 10 s. What is its acceleration?
State whether true or false. If false, correct the statement.
Acceleration can get negative value also.
If the velocity of a body does not change, then its acceleration is ______.
When a body starts from rest, the acceleration of the body after 2 seconds in ______ of its displacement.
Acceleration is defined as the rate of change of ______.
The value of acceleration for a body at rest is ______.
