Answer:
d = 2.54 [m]
Explanation:
Through the theorem of work and energy conservation, we can find the work that is done. Considering that the energy in the initial state is only kinetic energy, while the energy in the final state is also kinetic, however, this is zero since the body stops.
where:
W = work [J]
Ek1 = kinetic energy at initial state [J]
Ek2 = kinetic energy at the final state = 0.
We must remember that kinetic energy can be calculated by means of the following expression.
We know that work is defined as the product of force by distance.
where:
F = force [N]
d = distance [m]
But the friction force is equal to the product of the normal force (body weight) by the coefficient of friction.
Now solving the equation for the work.
Since velocity is vector quantity, it'll depend on both direction as well as magnitude hence options C and D are rejected.
Speed = distance/time
Therefore, unit of velocity is m/s.
Answer:
When it's closest to the sun.
Explanation:
The force of gravity acting on a planet is equal to its mass times its centripetal acceleration.
Fg = m v^2 / r
The force of gravity is defined by Newton's law of universal gravitation as:
Fg = mMG / r^2
Therefore:
mMG / r^2 = m v^2 / r
MG / r = v^2
v increases as r decreases. So the planet is moving fastest when it's closest to the sun, also known as the <em>perihelion</em>.
Answer:
the distance between the submarine and the ocean floor is 11,250 m
Explanation:
Given;
speed of the wave, v = 1500 m/s
time of motion of the wave, t = 15 s
The time taken to receive the echo is calculated as;
Therefore, the distance between the submarine and the ocean floor is 11,250 m
Answer:
12.4 m/s²
Explanation:
L = length of the simple pendulum = 53 cm = 0.53 m
n = Number of full swing cycles = 99.0
t = Total time taken = 128 s
T = Time period of the pendulum
g = magnitude of gravitational acceleration on the planet
Time period of the pendulum is given as
T = 1.3 sec
Time period of the pendulum is also given as
g = 12.4 m/s²