Advertisements
Advertisements
प्रश्न
A car of mass m starts from rest and acquires a velocity along east `v = vhati (v > 0)` in two seconds. Assuming the car moves with uniform acceleration, the force exerted on the car is ______.
विकल्प
`(mv)/2` eastward and is exerted by the car engine.
`(mv)/2` eastward and is due to the friction on the tyres exerted by the road.
more than `(mv)/2` eastward exerted due to the engine and overcomes the friction of the road.
`(mv)/2` exerted by the engine.
Advertisements
उत्तर
A car of mass m starts from rest and acquires a velocity along east `v = vhati (v > 0)` in two seconds. Assuming the car moves with uniform acceleration, the force exerted on the car is `underline((mv)/2)` eastward and is due to the friction on the tyres exerted by the road.
Explanation:
Given, the mass of the car = m
As the car starts from rest, u = 0
Velocity acquired along east = `vhati`
Duration = t = 2s.
We know that v = u + at
⇒ `vhati = o + a xx 2`
⇒ `s = v/2 hati`
Force, F = ma = `(mv)/2 hati`
Hence, the force acting on the car is `(mv)/2` towards the east. As the external force on the system is only friction hence, the force `(mv)/2` is by friction. Hence, force by the engine is internal force.
APPEARS IN
संबंधित प्रश्न
When a carpet is beaten with a stick, dust comes out of it. Explain.
If the speed of the stone is increased beyond the maximum permissible value, and the string breaks suddenly, which of the following correctly describes the trajectory of the stone after the string breaks?
A moving bicycle comes to rest after sometime if we stop pedalling it. But Newton’s first law of motion says that a moving body should continue to move for ever, unless some external force acts on it. How do you explain the bicycle case ?
Name the law involved in the following situation :
if there were no friction and no air resistance, then a moving bicycle would go on moving for ever.
Is it possible for a particle to describe a curved path if no force acts on it? Does your answer depend on the frame of reference chosen to view the particle?
The acceleration of a particle is zero, as measured from an inertial frame of reference. Can we conclude that no force acts on the particle?
The force exerted by the floor of an elevator on the foot of a person is more than the weight of the person if the elevator is
(a) going up and slowing down
(b) going up and speeding up
(c) going down and slowing down
(d) going down and speeding up
A block of mass 2 kg placed on a long frictionless horizontal table is pulled horizontally by a constant force F. It is found to move 10 m in the first seconds. Find the magnitude of F.
An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a frictionless horizontal table. The force required to keep this object moving with the same velocity is :
Give qualitative definition of force on the basic of Newton's first law of motion.
How does Newton's second law of motion differ from the first law of motion?
A force of 600 dynes acts on a glass ball of mass 200 g for 12 s. If initially, the ball is at rest, find
- Final velocity
- Distance covered.
Derive the relation between newton and dyne.
A man riding on a car has ___________ Inertia.
Classify the types of force based on their application.
When a bus suddenly takes a tum, the passengers are thrown outwards because of
Block A of weight 100 N rests on a frictionless inclined plane of slope angle 30° (figure). A flexible cord attached to A passes over a frictonless pulley and is connected to block B of weight W. Find the weight W for which the system is in equilibrium.
A force F is applied to the initially stationary cart. The variation of force with time is shown in the figure. The speed of the cart at t = 5 sec is ______.
What is the significance of Newton’s first law?
