A student is dragging a luggage trunk of mass 85 kg along a corridor with an acceleration of 0.18 ms2. The horizontal force the student exerts is 180 N. Find the frictional force between the floor and the trunk.
A car of mass 1200 kg is moving with a constant speed of 20 m s in a horizontal straight line, against a resisting force of 300 N. What driving force is being provided to sustain this motion? The driver speeds up uniformly over the next 30s to reach a speed of 30 ms. Assuming that the resisting force remains at 300 N, calculate the extra driving force produced.
A motorcyclist moves with an acceleration of 5 ms^-2 along a horizontal road against a total resistance of 120 N. The total mass of the rider and the motorcycle is 400 kg. Find the driving force provided by the engine.
A boy is pushing one side of a box, of mass m kg, with a force of 25 N. His sister is pushing from the opposite side of the box with a force of 13 N. The box does not move. Given that the frictional force resisting the motion has magnitude 3m N, calculate the value of m. The boy now pushes with an increased force of 35 N. Assuming that the frictional force remains as before, show that the box accelerates at 2.5 m s2.
Three men are trying to move a skip. Two of the men are pushing horizontally with forces of magnitude 120 N and 150 N and one man is pulling with a horizontal force of magnitude X N.
A jet plane of mass 30 tonnes touches down with a speed of 55 ms” and comes to rest after moving for 560 m in a straight line on the runway. Assuming that the only forces stopping the plane are provided by the reverse thrust of its two engines, and that these forces are equal and directed opposite to the direction of motion, calculate the magnitude of the thrust in each engine.
A bullet of mass 0.12 kg is travelling horizontally at 150 m s” when it enters a fixed block of wood. Assuming that the bullet’s motion remains horizontal and that the force resisting motion has constant magnitude 10 000 N. calculate how far the bullet penetrates the block.
A car of mass of 1000 kg runs out of petrol and comes to rest just 30 m from a garage. The car is pushed, with a force of 120 N, along the horizontal road towards the garage. Calculate the acceleration of the car and find the time it takes to reach the garage.
A boat of mass 3000 kg, travelling at a speed of um s”, is brought to rest in 20s by water resistance of 370 N. Find the value of u
A boy slides a box of mass 2 kg across a wooden floor. The initial speed of the box is 8 mi s and it comes to rest in 5 m. Calculate the deceleration of the box and find the frictional force between the box and the floor.
