Exam 6: Dynamics I: Motion Along a Line

A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N which is parallel to the slope.The coefficient of kinetic friction between the block and the slope is 0.200.What is the magnitude of the acceleration of the block?

15)Bumpers on cars are not of much use in a collision.To see why,calculate the average force a bumper would have to exert if it brought a 1200-kg car (a so-called compact model)to a rest in 15 cm when the car had an initial speed of 2.0 m/s (about 4.5 mph).(Bumpers are built with springs that compress to provide a stopping force without,hopefully,denting the metal.)

Kieran takes off from rest down a 50 m high,10° slope on his jet-powered skis.The skis have a thrust of 280 N parallel to the surface of the slope.The combined mass of skis and Kieran is 50 kg (the fuel mass is negligible).Kieran's speed at the bottom is 40 m/s.What is the coefficient of kinetic friction of his skis on snow?

A box slides down a frictionless plane inclined at an angle θ above the horizontal.The gravitational force on the box is directed

A block is on a frictionless horizontal table,on earth.This block accelerates at 1.9 m/ when a horizontal force is applied to it.The block and table are then set up on the moon where the acceleration due to gravity is 1.62 m/s².What is the weight of the block on the moon?

A block lies on a horizontal frictionless surface.A horizontal force of 100 N is applied to the block giving rise to an acceleration of 3.0 m/s². (a)Determine the mass of the block. (b)Calculate the distance the block will travel if the force is applied for 10 s. (c)Calculate the speed of the block after the force has been applied for 10 s.

A ship is being pulled through a harbor at constant velocity by two tugboats as shown in the figure.The lines attached to the two tugboats have the same tension of 200,000 N.Each line makes an angle of 28.0° with the direction the ship is being towed.What is the magnitude of the drag force due to the water on the ship?

A construction worker pulls a box of tools on a smooth horizontal floor with a force of 100 N in a direction of 37.0° above the horizontal.The mass of the box and the tools is 40.0 kg. (a)Draw a free-body diagram for the box. (b)Calculate the acceleration of the box. (c)How hard does the floor push up on the box?

Two objects have masses m and 5m,respectively.They both are placed side by side on a frictionless inclined plane and allowed to slide down from rest.

A 30.0-kg object experiences a drag force due to air resistance with a magnitude proportional to the square of its speed.The object falls with an acceleration of 4.00 m/s² downward when it is falling downward at 70.0 m/s.What is its terminal speed?

When a parachutist jumps from an airplane,he eventually reaches a constant speed,called the terminal speed.Once he has reached terminal speed

Jason takes off from rest across level water on his jet-powered skis.The combined mass of Jason and his skis is 75 kg (the mass of the fuel is negligible).The skis have a thrust of 200 N and a coefficient of kinetic friction on water of 0.10.Unfortunately,the skis run out of fuel after only 67 s.How far has Jason traveled when he finally coasts to a stop?

A 10,000-kg rocket blasts off from earth with a uniform upward acceleration of 2.00 m/s² and feels no air resistance.The upward thrust force its engines must provide during this acceleration is closest to

The following four forces act on a 4.00 kg object: ₁ = 300 N east ₂ = 700 N north ₃ = 500 N west ₄ = 600 N south What is the acceleration of the object?

A person is dragging a packing crate of mass 100 kg across a rough horizontal floor where the coefficient of kinetic friction is 0.400.He exerts a force F sufficient to accelerate the crate forward.At what angle above horizontal should his pulling force be directed in order to achieve the maximum acceleration?

A fish weighing 16 N is weighed using two spring scales,each of negligible weight,as shown in the figure.What will be the readings of the scales?

In a shuffleboard game,the puck slides a total of before coming to rest.If the coefficient of kinetic friction between the puck and the horizontal board is 0.28,what was the initial speed of the puck?

A 1.20-kg ball is hanging from the end of a rope.The rope hangs at an angle 25.0° from the vertical when a 15.0 m/s horizontal wind is blowing.If the wind's force on the rope is negligible,what drag force does the wind exert on the ball?

A block is given a very brief push up a 20.0° frictionless incline to give it an initial speed of 12.0 m/s. (a)How far along the surface of the plane does the block slide before coming to rest? (b)How much time does it take to return to its starting position?

A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle.The coefficients of static and kinetic friction between the hockey puck and the metal ramp are μ_s = 0.40 and μ_k = 0.30,respectively.The puck's initial speed is 63 m/s.What vertical height does the puck reach above its starting point?