Answer: 217.52 N
Explanation: The applied force is 20 N, the distance covered is 12.0 m and the angle is 25° above the horizontal.
Hence the formulae that defines work done is given by
W = Force × distance
But since the force has been inclined at an angle θ above the horizontal, the horizontal component of force is neccesary to produce the required motion to make the child do work on the wagon.
Hence
Work done = (horizontal component of force) × distance
Work done = F cos θ × distance
Work done = 20 cos 25 × 12 = 217.52 N
Take into account that density and relative density are given by:

Take into account that the volume associated to each of the given sustances in the table is determined by the Level Difference (because it is the change in the volume of the water of the recipient in which the substance is immersed).
The density of water in kg/m^3 is 1000 kg/m^3.
Due to the density must be given in kg/m^3, it is necessary to express the volumes of the table in m^3 and mass in kg, then, consider the following conversion factor:
1 m^3 = 1000000 ml
1 kg = 1000 g
Then, you obtain the following results:
Brass:

Cooper:
Answer:
Newton's first law
Explanation:
Newton's first law states that if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. Therefore, when the ice is smooth, friction gets lesser, and the force acted on that Puck will be decreased.
A big part of the reason that mirrors are seldom if ever used to generate
electricity is the simple fact that there is no way to generate electricity using
mirrors. They are as useless for the purpose as smoke is, although there are
those who have used both items simultaneously to create the impression that
they have succeeded in that attempt.