7637

Physics Work,Power & Energy Level: Misc Level

An object with a mass of 0.75 kg is dropped from rest from a height h=3.0 m above the top of a vertical spring that has spring constant k= 300 N/m.Draw a picture' a) Find the speed of the object when the spring is compressed 0.2 m. b) Find the compression of the spring when the object reaches its lowest point. c) After leaving the spring, how high above the top of the relaxed spring does the object rise before coming to rest.Explain the reasoning used for this question.


7636

Physics Work,Power & Energy Level: Misc Level

A block of mass M is placed on a plane of length L which is inclined at an unknown angle with respect to the horizontal. There is friction between the block and the surfaces, so a gentle nudge is required to start the block moving. Assume this nudge is sufficiently gently so that the initial speed of the block is zero.When the block reaches the bottom of the incline, it slides along the table top until coming to rest a distance L from the bottom of  the incline.a) What is the work done by the normal force that the plane exerts on the block? b)What is the work done by gravity during the entire motion? c)How is the work done by friction during the entire motion related to the work done by gravity?  Explain all reasoning.


7635

Physics Work,Power & Energy Level: Misc Level

An object slides without friction around a loop-the -loop. If the object is released from rest at a height h=3.5 R, a) what is its speed at the top of the loop? b) How large is the normal force on the object when it is at the top of the loop if its mass is 5 g?


7623

Physics Work,Power & Energy Level: Misc Level

(no pciture) A 0.024 kg bullet is fired straight up at a falling wooden block that has a mass of 3.0 kg.The bullet has a speed of 670 m/s when it strikes the block. The block originally was dropped from rest from the top of a building and had been falling for a time t when the collision with the bullet occured. As a result of the collision, the block (with the bullet in it) reverses direction, rises, and comes to a mo0mentary halt at the top of the building. Find the time t.s


7617

Physics Work,Power & Energy Level: Misc Level

A child on a sled slides down an incline with a 20 degree slope.the incline is 10 meters long.The coefficient of kinetic friction is 0.12.Using Newton,s method and energy methods; the mass of the child and sled is 25 kg

a) Find the force of friction

b)Find the acceleration down the hill

c)Find the work done by the friction force

d) Find the kinetic energy and velocity at the bottom of the hill.


7519

Physics Work,Power & Energy Level: Misc Level

Bobby accelerates from rest at 121 m/s2 for 1.2 seconds. He then runs along level ground at that speed until he jumps onto a stationary wagon fully loaded with large cement blocks. The wagon and the blocks have a total mass of 122 kg.(No friction involved in this problem. It,s a frictionless environment,) As the wagon, with Bobby on board, rolls along it encounters a hill inclined upward at 15 degrees. The wagon then rolls up the hill a distance of 11.3 m ( along the ground) before coming to a stop.Determine Bobby,s mass.


7463

Physics Work,Power & Energy Level: Misc Level

A 75 kg cross country .skier glides over snow.the coefficient of friction between skis and snow is 0.20.Assume all the snow beneath his skis is at 0 oc and that all the internal energy generated by friction is added to snow that sticks to his skis until melted. How far would he have to ski to melt 1.0 kg of snow?


7462

Physics Work,Power & Energy Level: Misc Level

A siphon is a device that allows a fluid to seemingly defy gravity.The flow must be initiated by a partial vacuum in the tube,as in a drinking straw.a)show that the speed at which the water emerges from the siphon is given by v=sqrt (2gh). b) for what values of y will the siphon work?


7460

Physics Work,Power & Energy Level: Misc Level

[Walker2 9.p.019.] An object initially at rest breaks into two pieces as the result of an explosion. One piece (m2) has four times the kinetic energy of the other piece (m1). What is the ratio of the masses of the two pieces?

m1/m2= Which piece has the larger mass?The masses must be equal. The piece with the larger kinetic energy. The piece with the smaller kinetic energy.


7444

Physics Work,Power & Energy Level: Misc Level

A 50 kg crate slides down a 5.0 m loading ramp that is inclined at an angle of 25% to the horizontal.A worker pushes on the crate parallel to the surface of the ramp so that the crate slides down with a constant velocity. If the coefficient of kinetic friction between the crate and the ramp is 0.33, how much work is done by each of the following?(a)the worker,(b)the force of friction, (c) the force of gravity, (d) what is the net work done on the crate?


7443

Physics Work,Power & Energy Level: Misc Level

A constant horizontal force of 28 N moves a box with a constant speed along a rough surface. If the force does work at a rate of 50 w, answer the following.(a) what is the box,s speed? (b) How much work is done by the force in 2.7 s?


7442

Physics Work,Power & Energy Level: Misc Level

A particular force is described by the equation F=(60 N/m) x x.How much work is done when this force pushes a box horizontally between the following points?(a)x0=0 and x=0.12 m, (b)x0=0.15 m and x=0.26 m


7426

Physics Work,Power & Energy Level: Misc Level

A (n) 6.5 g bullet is fired into a (n) 1.8 kg ballistic pendulum. The bullet emerges from the block with a speed of 176 m/s, and the block rises to a maximum height of 8 cm.The acceleration of gravity is9. 8 m/s squared. Find the initial speed of the bullet. Answer in units of m/s.


7423

Physics Work,Power & Energy Level: Misc Level

A 0.246 kg puck, initially at rest on a horizon-tal, frictionless surface, is struck by a 0.169 kg puck moving initially along the x axis with a speed of 2.2 m/s.After the collision, the 0.169 kg puck has a speed of 1.2 m/s at an angle of 38 degrees to the positive x axis. Determine the velocity of the 0.246 kg puck after the collision. Answer in units of m/s.


7422

Physics Work,Power & Energy Level: Misc Level

A 2123 kg car moving east at 10.64 m/s col-lides with a 3204 kg car moving north. The cars stick together and move as a unit after the collision, at an angle of 38.1 degrees north of east and at a speed of 5.39 m/s.What was the speed of the 3204 kg  car before the collision? Answer in units of m/s.


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