Answer:
c) nonzero, directed toward the spaceship
Explanation:
As we know that net gravitational force due to spherical shell inside all its points will always be zero
So if planet is a spherical shell then inside the planet net gravitational force is zero on the people living in it
So when massive spaceship land on the surface of planet then the gravitational force of the spaceship is experienced by the people inside the shell
So here the gravitational force on the people is nonzero and it is towards the spaceship which landed on the surface of planet
Answer:
t=20s
Explanation:
To solve this problem we must apply the first law of thermodynamics, which indicates that the energy that enters a system is the same that must come out, resulting in the following equation
For this problem we will assume that the water is in a liquid state, since it is a domestic refrigerator
q=m.cp.(T2-T1)
q=heat
m=mass of water =600g=0.6Kg
cp=
specific heat of water=4186J/kgK
T2=temperature in state 2=20°C
T1=temperature in state 1=0°C
solving:
q=(0.6)(4186)(20-0)=50232J
A refrigerator is a device that allows heat to be removed to an enclosure (Qin), by means of the input of an electrical energy (W) and the heat output (Qout), the coefficient of performance COP, allows to know the ratio between the heat removed ( Qin) and the added electrical power (W), the equation for the COP is

To solve this exercise we must know the value of the heat removed to the water (Qin)
solving for Qin
Qin=(COP)(Win)
Qin=(5)(500W)=2500W
finally we remember that the definition of power is the ratio of work over time
w=work
p=power=500w

Answer:
3,200,000,000 J
Explanation:
Work is defined as the amount of energy transferred as an object is moved a certain distance with a certain force. Mathematically, we express this with the equation

where W is work (measured in joules), F is the force applied (in Newtons), and s is the distance, also called the <em>displacement </em>(in meters).
Here, we have F = 1,600,000 N and s = 2000 m, so our work will be
J
Answer:
Momentum is directly proportional to velocity. If momentum of an object is doubled , but its mass does not increase (so velocity remains below the speed of light) then its velocity is doubled. If the velocity is doubled, then the kinetic energy increases by four times.
Explanation:
Hope it is helpful....