Advertisements
Advertisements
Question
A 1000 kg vehicle moving with a speed of 20 m/s is brought to rest in a distance of 50 metres :
(i) Find the acceleration.
(ii) Calculate the unbalanced force acting on the vehicle.
Advertisements
Solution
(i) Final velocity, v = 0 (because the car is brought to rest)
Distance covered, s = 50 m
So, Force = mass × acceleration
But we do not know the value of a.
Making use of the third equation of motion we get,
v2 − u2 = 2as
⇒ 0 − 202 = 2 × a × 50
⇒ −400 = 100a
⇒ a = −4
The acceleration = −4 m/s2
(ii) Force = mass × acceleration
Mass = 1000 kg
Force = 1000 × (−4)
= − 4000 N
Unbalanced force acting on the vehicle is −4000 N.
APPEARS IN
RELATED QUESTIONS
An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on the magnitude and direction of the velocity. If no, provide a reason.
What is the usual name of the forces which cannot produce motion in a body but only change its shape ?
Explain why, it is dangerous to jump out of a moving bus.
Give one example where a force changes the shape (and size) of a body.
What is the relationship between force and acceleration ?
When we talk of a force acting on a body, it usually means :
If we release a magnet held in our hand, it falls to the ground. The force which makes the magnet fall down is an example of :
When a rubber balloon held between the hands is pressed, its shape changes. This happens because :
A fielder pulls his hands backwards after catching the cricket ball. This enables the fielder to :
Why does it happen?
If a stationary bus suddenly speeds up, passengers are thrown in the backward direction.
