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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
State the type of motion represented by the following sketches in Figures.
Give an example of each type of motion.
Figure given below shows a velocity-time graph for a car starting from rest. The graph has three parts AB, BC and CD.
(a) Is the magnitude of acceleration higher or lower than that of retardation ? Give a reason .
(b) Compare the magnitude of acceleration and retardation .
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.
Explain the following concept in your own words with everyday examples:
Acceleration
A racing car is moving with a velocity of 50 m/s. On
applying brakes, it is uniformly retarded and comes to rest in 20 seconds. Calculate its acceleration.
From the diagram given below, calculate acceleration.
Diagram is given below shows velocity – time graph of car P and Q, starting from the same place and in the same direction. Calculate the Acceleration of car Q between 2 s – 5 s.
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.
What is the SI unit of 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.
Write the SI unit of acceleration and retardation.
Can you use the relation [B1]?
The graph shows how the velocity of a scooter varies with time in 50 s.
Work out: Deceleration
A car accelerates to a velocity of 30 m/s in 10 s and then decelerates for 20 s so that it stops. Draw a velocity-time graph to represent the motion and find:
The acceleration.
m/s2 is the unit of ______.
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 ______.
An object can be moving with uniform speed but with variable acceleration.
It is possible to have objects moving with uniform speed but variable acceleration.
Assertion: A positive acceleration of a body can be associated with the slowing down of the body.
Reason: Acceleration is a vector.
