Explanation:
The rod is uniform, so the center of gravity is at the center, or 0.75 m from the end. The wedge is 0.5 m from the end, so the center is 0.25 m from the wedge.
Sum the torques about the wedge (it may help to draw a diagram first). Take counterclockwise to be positive.
∑τ = Iα
W (0.25 m) − (100 N) (0.50 m) = 0
W = 200 N
Sum the forces in the y direction.
∑F = ma
F − 100 N − 200 N = 0
F = 300 N
Answer:
Work done in all the three cases will be the same.
Explanation:
1) The free falling body has only one force acting on it, the gravitational force. The work done on the body = mgH (Gravitational potential energy)
2) There are two forces acting on the body going down on a frictionless inclined plane - gravity and the normal force. The gravitational potential energy will be the same. The work done due to the normal force is zero, since the direction of the force is perpendicular to the displacement. Hence, total work done on the body = mgH
3) In the case of the body swinging on the end of a string, the change in gravitational potential enrgy will once again be the same since difference in height is H. The additional force on the body is the tension due to the string. But the work done due to this force is <em>zero, </em>since the displacement of the body is perpendicular to the tension. Therefore, the total work done on the body is once again mgH.
Answer:
a) For the passenger the ball is seen to go up in a straight line path, and fall back to the hands of the passenger in a straight line path.
b) For a stationary observer on the ground, the ball is seen to take a parabolic path from when it is thrown up to when it fall down back on the palms of the passenger.
Explanation:
If a ball is thrown up in a vehicle moving with a constant velocity, the ball will be seen as the passenger, who is on the same frame of reference as the ball, to go up and down in a vertical straight line path. For an observer on the ground, this is different, as the ball is seen to to have both a relative vertical and horizontal component of motion, making the ball take a parabolic path from the time it was thrown, to when it falls back to the hands of the passenger.
