The driver of a three wheeler moving with a speed of `36 km//h` sees a child standing in the middle of the road and brings his vehicle to rest in 4 s just in time to save the child What is the average retarding force on the vehicle ? The mass of three wheeler is 400 kg and mass of the driver is 65 kg .

A sooterist moving with a speed of 36kmh^(-1) sees a child standing in the middle of the road. He applies the brakes and brings the scooter to rest in 5 s just in time to save child. Calculate the average retarding force on the vehicle, if mass of the vehicle and driver is 300 kg.

A railway engine (mass 10^(4) kg) is moving with a speed of 72 km/h. The force which should be applied to bring it to rest over a distance of 20m is

A driver is driving a car at a speed of 90km/h. he spots a child standing on his way and decided to apply the brakes but it took him 0.3s to actually apply the brakes. If the retardation produced by the brakes is 10m//s^(2) , calcualtion the total distance covered by car before coming to rest

A car moves on a road with a speed of 54 km h^(-1) . The radius of its wheels is 0.35 m . What is the average negative torque transmitted by its brakes to the wheels if the car is brought to rest in 15 s ? Moment of inertia of the wheels about the axis of rotation is 3 kg m^(2) .

A (trolley + child) of total mass 200 kg is moving with a uniform speed of 36 km/h on a frictionless track. The child of mass 20 kg starts running on the trolley from one end to the other (10 m away) with a speed of 10 ms^(–1) relative to the trolley in the direction of the trolley's motion and jumps out of the trolley with the same relative velocity. What is the final speed of the trolley? How much has the trolley moved from the time the child begins to run?

An autmobile moves on road with a speed of 54 km//h . The radius of its wheel is 0.45 m and the moment of inertia of the wheel about its axis of rotation is 3 kg m^(2) . If the vehicle is brought to rest in 15 s , the magnitude of average torque tansmitted by its brakes to the wheel is :

A car of mass 900 kg accelerates uniformly from rest to a speed of 60 km/h in a time of 2 s when traveling on a level road. If there is a constant resistance to motion of 20 N. Find the maximum power ( in kW) of the engine.

A boat is travelling in a driver in river with a speed 10 m//s along the stream flowing with a speed 2m//s . From this, boat, a sounjd transmitter is lowered into the river through a right support. The wavelength of the sound emitted from the transmitter inside the water is 14.45 mm . Assume that attention of sound in water and air is negligible. (a) What will be frequency detected by receiver kept inside downstream? (b) The transmitter and the receiver are now pulled up into air. The air is blowing with a speed 5 m//s in the direction opposite the river stream. Determine the frequency of the sound detected by the receiver. (Temperature of the air and water = 20^(@)C , Density of river water = 10^(3) kg//m^(3) . Bulk modulus of the water = 2.088 xx 10^(6) Pa , Gas constant R = 8.31 J//mol-K , Mean molecular mass of air = 28.8 xx 10^(-3) kg//mol , C_(P)//C_(V) for air = 1.4 ).

A scooter of mass 150 kg is moving with a uniform velocity of 108 km/h. Then the force required to stop he vehicle in 10s is