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प्रश्न
What do you understand about negative acceleration?
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उत्तर
If v < u, i.e. if final velocity is less than initial velocity, the velocity decreases with time and the value of acceleration is negative. It is called negative acceleration. It is also called as retardation (or) deceleration.
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संबंधित प्रश्न
A toy car initially moving with uniform velocity of 18 km h-1 comes to a stop in 2 s. Find the retardation of the car in S.I. units.
A train starts from rest and accelerates uniformly at a rate of 2 m s−2 for 10 s. It then maintains a constant speed for 200 s. The brakes are then applied and the train is uniformly retarded and comes to rest in 50 s. Find
- The maximum velocity reached,
- The retardation in the last 50 s,
- The total distance travelled,
- The average velocity of the train.
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?
Give an example of an accelerated body, moving with a uniform speed.
A motor bike running at 90 kmh−1 is slowed down to 18 kmh−1 in 2.5 s. Calculate
- acceleration
- distance covered during slow down.
Write the SI unit of retardation.
State if the following situation is possible:
A body moving with constant acceleration but with Zero velocity.
Is it possible for an accelerating body to have constant speed?
A car is being driven at a speed of 20ms-1 when brakes are applied to bring it to rest in 5 s. The deceleration produced in this case will be ______.
Assertion: When a body is subjected to a uniform acceleration, it is always moving in a straight line.
Reason: Motion may be straight-line motion or circular motion.
