Exam 4: Applying Newtons Laws

A hockey puck slides off the edge of a horizontal platform with an initial velocity of 20 m/s horizontally.The effects of air are negligible.The height of the platform above the ground is 2.0 m.What is the magnitude of the vertical component of the velocity of the puck just before it hits the ground?

A projectile is fired from ground level on a horizontal plain.If the initial speed of the projectile is now doubled,and we neglect air,

A 10-kg sign is held by two ropes as shown in the figure.What is the tension force that rope A exerts on the sign?

During a hockey game,a puck is given an initial speed of 10 m/s.It slides 50 m on the horizontal ice before it stops due to friction.What is the coefficient of kinetic friction between the puck and the ice?

A 55-kg box rests on a horizontal surface.The coefficient of static friction between the box and the surface is 0.30,and the coefficient of kinetic friction is 0.20.What horizontal force must be applied to the box to cause it to start sliding along the surface?

Three boxes rest side-by-side on a smooth,horizontal floor.Their masses are 5.0 kg,3.0 kg,and 2.0 kg,with the 3.0-kg mass in the center.A force of 50 N pushes on the 5.0-kg box,which pushes against the other two boxes.What magnitude force does the 5.0-kg box exert on the 3.0-kg box?

Three objects are connected by weightless flexible strings as shown in the figure.The pulley has no appreciable mass or friction,and the string connected to the block on the horizontal bench pulls on it parallel to the bench surface.The coefficients of friction between the bench and the block on it are µ_s = 0.66 and µ_k = 0.325.You observe that this system remains at rest. (a)Find the mass of the hanging object A. (b)What is the magnitude of the friction force exerted on the block on the bench?

A displacement vector is 34.0 m in length and is directed 60.0° east of north.Selecting from the choices in the table below,what are the components of this vector? Northward Eastward Choice component component 1 29.4 m 17.0 m 2 18.2 m 28.1 m 3 22.4 m 11.5 m 4 17.0 m 29.4 m 5 25.2 m 18.2 m

A fisherman casts his bait toward the river at an angle of 25° above the horizontal.As the line unravels,he notices that the bait and hook reach a maximum height of $2.9 \mathrm {~m}$ What was the initial velocity he launched the bait with? Assume that the line exerts no appreciable drag force on the bait and hook and that is the effects of air are negligible.

A 200-N sled of slides down a frictionless hillside that rises at 37° above the horizontal.What is the magnitude of the force that the surface of the hill exerts on the sled?

Two forces are exerted on a $55 - \mathrm { kg }$ object.One force has magnitude 65 N directed 59° clockwise from the positive x-axis,and the other has a magnitude 35 N at 32° clockwise from the positive y-axis.Assuming no other forces,what is the magnitude of this object's acceleration?

A block of mass m sits at rest on a rough inclined ramp that makes an angle θ with the horizontal.What must be true about the force F that the ramp exerts on the block perpendicular to the surface of the ramp?

A child is trying to throw a ball over a fence.She gives the ball an initial speed of 8.0 m/s at an angle of 40° above the horizontal.The ball leaves her hand 1.0 m above the ground and the fence is 2.0 m high.The ball just clears the fence while still traveling upwards..How far is the child from the fence if you neglect air?

Shown below are the velocity and acceleration vectors for an object in several different types of motion.In which case is the object slowing down and turning to its right?

A 7.5-kg stone moves up frictionless hill that slopes upward at 41° above the horizontal.If the stone has an initial velocity of 8.5 m/s at the bottom,how far (as measured along the surface of the hill)will it go before stopping?

A piano mover raises a 1000-N piano at a constant speed using a very light rope in a frictionless pulley system,as shown in the figure.What is the force that the mover is exerting on the rope?

A player kicks a soccer ball in a high arc toward the opponent's goal.At the highest point in its trajectory

In the figure,block A has a mass of 3.00 kg.It rests on a smooth horizontal table and is connected by a very light horizontal string over an ideal pulley to block B,which has a mass of 2.00 kg.When block B is gently released from rest,how long does it take block B to travel 80.0 cm?

A 590-kg rocket is at rest on the launch pad.What upward thrust force is needed to accelerate the rocket uniformly to an upward speed of 28 m/s in 3.3 s?

Calculate the average force an outside object would have to exert to bring a 1200-kg car to rest in 15 cm when the car had an initial speed of 2.0 m/s (about 4.5 mph).