Answer:
v'=5.97 m/s
Explanation:
If the friction and fluid friction are ignored, then by law of conservation of mechanical energy, potential energy at the top of the slide must be equal to the kinetic energy at the bottom of the slide. Thus, the height of slide and final speed at the bottom of the slide are related as:
let the final speed be v' when h' = 2 h
Answer:
None of the statement is false - all of them are true
Explanation:
Let's analyze each statement:
- The net force on the block is zero newtons. --> TRUE. In fact, the block is moving across the surface at constant speed: constant speed means zero acceleration, and according to Newton's second law,
F = ma
this also means a net force of zero newtons.
- The frictional force on the block has magnitude 3.0 N. --> TRUE. The horizontal acceleration of the block is zero, so the resultant of the horizontal forces must be zero:
where F = 3.0 N is the horizontal push and is the frictional force. From the equation, we find
- The coefficient of kinetic friction between the block and the surface is 0.30. --> TRUE. The frictional force is 3.0 N, and its expression is
where is the coefficient of kinetic friction and (mg)=10 N is the weight of the block. Solving for
, we find
- The direction of the total force that the surface exerts on the block is vertically upward. --> TRUE. Since gravity is acting downward, and the block is not accelerating on the vertical direction neither, there must be an equal and opposite force acting upward on the block: and this force is the force exerted by the surface on the block.
- The block is not accelerated. --> TRUE: the block is moving at constant speed, so its acceleration is zero.