Answer:
5 x 10⁻⁷N
Explanation:
Given parameters:
Mass of object 1 = 100kg
Mass of object 2 = 300kg
Distance = 2m
Unknown:
Force of gravitational attraction between the objects = ?
Solution:
From Newton's law of universal gravitation we derive an expression:
Fg = 
G is the universal gravitation constant = 6.67 x 10⁻¹¹
m is the mass
r is the distance between the bodies
Now insert the parameters and solve;
Fg = 6.67 x 10⁻¹¹ x 
= 5 x 10⁻⁷N
Answer:
If you try to lift up a weight in a swimming pool and then try to lift the same weight on the edge of the pool, it feels much lighter in the water.
This was supposed to have been first explained by the Greek scientist Archimedes. He said that the water gives an upward force or upthrust on any object in it.
You can weigh an object in air and then in water and actually work out the upthrust, it is the difference between the two readings. For this reason the upthrust is often called the loss in weight of the object.
Answer:
<em>The correct choice is D. Its gravitational potential energy must increase</em>
Explanation:
<u>Conservation of Mechanical Energy</u>
The total amount of mechanical energy, in a closed system in the absence of dissipative forces like friction or air resistance, remains constant.
This means that energy cannot disappear or appear and that potential energy can become kinetic energy or vice versa.
In a closed system like a pendulum, two types of energies are considered: Gravitational potential (U) and kinetic (K). Thus, the sum of both energies must remain constant in time.
Suppose the pendulum is at a state where U=150 J, and K=350 J. The total mechanical energy is:
M = 150 J + 350 J = 500 J
If the kinetic energy decreases to a new value, say K = 200 J, then the gravitational potential must increase to compensate for this new condition, that is: U = 300 J
The correct choice is D. Its gravitational potential energy must increase
Answer: D
Explanation:
Kinetic energy = 1/2mV^2
From the formula above, we can deduce that kinetic energy is proportional to the square of speed. That is,
K.E = V^2
Graphically, the relationship isn't linear but a positive exponential. Therefore, option D is the correct answer.
