Home
Class 11
PHYSICS
A car weighing 1400 kg is moving at spe...

A car weighing 1400 kg is moving at speed of 54 km/h up a hill when the motor stops. If it is just able to read the destination which is at a height of 10 m above the point calculte the work done against friction (negative of the work done by the friction).

Text Solution

Verified by Experts

The correct Answer is:
B, C
`m=1400kg`
`v=54km/h=15m/sec`
`h=10m`
Work done= (total K.E.)-total P.E.`
=(1/20mv^2-mgh`
`=1/2xx1400xx(15)^2-1400xx9.8xx10`
`=+157500-137200=20300j`
`so, work done against friction `W_1=20300J`
Promotional Banner

Similar Questions

Explore conceptually related problems

If a friction of 200 N exerted opposite to the motion of a object dragged up to 10m , then what will be the work done by the friction force on the road ?

A car weighing 1000 kg is travelling at the speed of 15ms^(-1) . It decelerated due to brakes applied and stops after covering a distance of 25 m. Find the force exerted by the brakes and the work done by the brakes.

On complete combustion a litre of petrol gives off heat equivalent to 3 xx 10^(7) J. In a test drive, a car weighing 1200 kg including the mass of driver, runs 15 km per litre while moving with a uniform speed on a straight track. Assuming that friction offered by the road surface and air to be uniform. calculate the force of friction acting on the car during the test drive. if the efficiency of the car engine were 0.5.

A block of mass 1 kg is pushed up a surface inclined to horizontal at an angle of 30^(@) by a force of 10 N parallel to the inclined surface (figure) . The coefficient of friction between block and the incline is 0.1 .If the block is pushed up by 10 m along teh inclined calculate (a) work done against gravity (b) work done against force of friction (c ) increases in potential energy (d) increases in kinetic energy (e) work done by applied force

A small sphere of mass m is dropped from a aheight After it has fallen 100 m it has attained its terminal velocity and continues to fall at that speed. The work done by air friction against the sphere during the first 100 m of fall is-

A body of mass 2 kg initially kg intially at rest moves under the action of an applied horizontal force of 7 N on a table with coefficient of kinetic friction = 0.1 Compute the (a) work done by the applied force in 10 s. (b) work done by friction in 10 s . work done by the net force on the body in 10 s. (d) Change in kinetic energy of the body in 10 s and interpret your details .

A rain drop of radius 2 mm falls from a height of 500 m above the ground .It falls with decreasing acceleration (due to viscous resistance of the air) until at half its original height , it attains its maximum (terminal) speed, and moves with uniform speed thereafter .What is the work done by the gravitational force on the drop in the first and second half of its journey ?What is the work done by the resistive force in the entire journey if its speed on reaching the ground is 1 ms^(-1) ?