Answer:They act on different bodies
Explanation:
Newton's third law of motion states that for every action there is equal and opposite reaction i.e. action and reaction. Though action and reaction are equal they act in different bodies that is why they do not cancel out each other.
For example, a block of mass m placed over the table exerts a force of mg to the table while the table applies a Normal reaction of equal magnitude as of mg to the block of mass m.
Answer:
Δ KE = -495 J
Explanation:
given,
mass of the ice hockey player = 110 Kg
initial speed = 3 m/s
final speed = 0 m/s
distance, d = 0.3 m
change in kinetic energy


Δ KE = -495 J
Hence, the change in kinetic energy is equal to Δ KE = -495 J
Answer:
Yes, a body with a certain velocity can have an opposite acceleration, the acceleration would then be negative, since it is opposite to the direction to the velocity and also because the direction in which the acceleration is portrayed is on the left-hand side.
Hope this answer helps :)
Answer:
2. The metal surface exerts less frictional force because there are fewer bumps and irregularities on it than there are on the concrete.
Explanation:
Frictional force is a force that is exerted between two surfaces in contact with each other. Frictional force always opposes the direction of relative motion of the two surfaces: for instance, for a ball moving along a surface, the force of friction exerted by the surface on the ball points opposite to the direction of motion of the ball.
The magnitude of the frictional force for a ball moving on a flat surface is given by

where
is the coefficient of friction
m is the mass of the ball
g is the acceleration of gravity
The value of
depends on the type of surface involved. In particular, a smooth surface has a smaller value of
, while a rough surface will have a bigger value. In this case, we are comparing a smooth metal surface with concrete: since the metal surface has fewer bumps and irregularities than concrete, it has a smaller value of coefficient of friction, so it exerts less frictional force than concrete.
Answer:
The increase in the gravitational potential energy is 29.93 joules.
Explanation:
Given that,
Mass of the box, m = 2.35 kg
It is lifted from the floor to a tabletop 1.30 m above the floor, h = 1.3 m
We need to find the increase the gravitational potential energy. Initial it will placed at ground i.e. its initial gravitational potential is equal to 0. The increase in the gravitational potential energy is given by :


U = 29.93 Joules
So, the increase in the gravitational potential energy is 29.93 joules. Hence, this is the required solution.