Advertisements
Advertisements
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.
Advertisements
उत्तर
initial velocity (u) = 18 km/h-1
final velocity (v) = 0 km/h
time (t) = 2 s
acceleration/retardation (a) = ?
To convert initial velocity u to m s-1
18 km/h-1 = `(18 " km")/(1 " h")`
= `(18 xx 1000 " m")/(60 xx 60 " s")`
⇒ 18 km/h-1 = `(18 xx 10 " m")/(6 xx 6 " s")`
⇒ 18 km/h-1 = 5 m s-1
Acceleration (a) = `("Final Velocity "("v") - "Initial Velocity "("u"))/("time "("t"))`
a = `(0 - 5)/2` m s-2
a = `-(5 "ms"^-1)/"2s"`
a = -2.5 m s-2
Hence, acceleration of the body is -2.5 m s-2. Negative sign shows that the velocity decreases with time, so retardation is 2.5 m s-2.
APPEARS IN
संबंधित प्रश्न
An object of mass 16 kg is moving with an acceleration of 3 m/s2. Calculate the applied force. If the same force is applied to an object of mass 24 kg, how much will be the acceleration?
What is meant by the term retardation? Name its S.I. unit.
The unit of retardation is ____________
If a body is moving with a constant velocity its acceleration is ______.
The change in velocity of a motorbike is 54 kmh−1 in one minute. Calculate its acceleration in (a) ms−2 (b) kmh−2.
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.
State if the following situation is possible:
A body moving with a constant velocity in an accelerated motion.
Correct your friend who says that acceleration gives the idea of how fast the position changes.
State whether true or false. If false, correct the statement.
Acceleration can get negative value also.
Assertion: The accelerated motion of an object may be due to change in magnitude of velocity or direction or both of them.
Reason: Acceleration can be produced only by change in magnitude of the velocity. It does not depend the direction.
