# Physcis

An object slides without friction in a bowl shaped like a hemisphere. It is released from rest at one edge of the bowl, slides up the other side before stopping right on the edge of the bowl. During which part of this process is the power being delivered by the gravitational force at is greatest? Not that we want the greatest positive power.

A. At the beginning
B. When the object is at the bottom of the bowl.
C. At the end
D. Sometime between the start and when the object reaches the bottom of the bowl.
E. Sometime between when the object reaches the bottom of the bowl and the end.

1. 👍 0
2. 👎 0
3. 👁 293
1. Power delivered by gravity is the product of speed and the gravity (weight) component along the side of the bowl.
Let A be the angle to the object, measured from the center of the hemisphere.
Speed = sqrt(2gRsinA)
Weight component along direction of motion:
M g cos A
Power = M g cosA*sqrt(2 g R sin A)
Power is zero at A = 0 and 90 degrees, and is a maximum somewhere in between. To be positive, the answer must be D.

1. 👍 0
2. 👎 0
2. Thank you for such a wonderful explanation

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Physics

a small rock with mass 0.20 kg is released from rest at point A which is at the top edge of a large, hemispherical bowl with radius R = .5m. assume that the size of the rock is small compared to R, so that the rock can be treated

asked by Frankie on October 23, 2012
2. ### physics

A 0.5 kg object is given an initial velocity of 3 m/s after which it slides a distance of 8 m across a level floor. What is the coefficient of kinetic friction between the object and the floor?

asked by Hussein on February 14, 2018
3. ### Physics

A 910kg object is released from rest at an altitude of 1200 km above the north pole of the earth. If we ignore atmospheric friction, with what speed does the object strike the surface of the earth? (the polar radius of the earth

asked by Anonymous on March 6, 2016
4. ### Physics

A 5kg object placed on a friction-less, horizontal table connected to a string that passes over a pulley and then is fastened to a hanging 9kg object. (A) Draw a free body diagram of both the objects. (B) The Coefficient of

asked by Kampamba Nsofu on May 24, 2017
1. ### physics

The three blocks shown are released from rest and are observed to move with accelerations that have a magnitude of 1.5 m/s^2. Disregard any pulley mass or friction in the pulley and let M = 2 kg. a) What is the magnitude of the

asked by Anonymous on March 16, 2018
2. ### physics

A 910kg object is released from rest at an altitude of 1200 km above the north pole of the earth. If we ignore atmospheric friction, with what speed does the object strike the surface of the earth?

asked by Anonymous on March 6, 2016
3. ### Physics

A 215 g particle is released from rest at point A (the middle of one side) inside a smooth hemispherical bowl of radium 30.0 cm. Calculate the gravitational potential energy at A relative to B. (B is in bottom-middle of the bowl)

asked by Becca on December 5, 2006
4. ### physics

A solid ball is released from rest and slides down a hillside that slopes downward at an angle 52.0 from the horizontal.What minimum value must the coefficient of static friction between the hill and ball surfaces have for no

asked by amena on May 29, 2011
1. ### physics

A 1.75-kg block is at rest on a ramp of height h. When the block is released, it slides without friction tothe bottom of the ramp, and then continues across a surface that is frictionless except for a rough patch of width 10.0 cm

asked by mary on January 18, 2011
2. ### PHYSICS

A 2.5 g ice flake is released from the edge of a hemispherical bowl whose radius r is 40.0 cm. The flake-bowl contact is frictionless. (a) What is the speed of the flake when it reaches the bottom of the bowl? (b) If a second

asked by Anonymous on October 21, 2011
3. ### Physics

A hanging spring stretches by 30.0 cm when an object of mass 490 g is hung on it at rest. We define its position as x = 0. The object is pulled down an additional 20.0 cm and released from rest to oscillate without friction. What

asked by Victoria on April 16, 2013
4. ### Physics

A hot-air balloon is rising vertically at a speed of 10 m s–1. An object is released from the balloon. The graph shows how the velocity of the object varies with time from when it leaves the balloon to when it reaches the ground

asked by tania on February 16, 2011