Answer:
Explanation:
This is a problem based on time dilation , a theory given by Albert Einstein .
The formula of time dilation is as follows .
t₁ = 
t is time measured on the earth and t₁ is time measured by man on ship .
A ) Given t = 20 years , t₁ = ? v = .4c

=1.09 x 20
t₁= 21.82 years
B ) Given t = 5 years , t₁ = ? v = .2c

=1.02 x 5
t₁= 5.1 years
C ) Given t = 10 years , t₁ = ? v = .8c

=1.67 x 10
t₁= 16.7 years
D ) Given t = 10 years , t₁ = ? v = .4c

=1.09 x 10
t₁= 10.9 years
E ) Given t = 20 years , t₁ = ? v = .8c

=1.67 x 20
t₁= 33.4 years
Answer:
d: ice is less dense than liquid water.
Explanation:
hope this helps! ( brainliest would be appreciated :)
~mina
Answer: B
Explanation:
The equation to find momentum is velocity*mass. Without velocity, there would be no momentum. Therefore the object CAN NOT be at rest.
Answer:
It will continue moving at a constant speed because no forces are acting on it.
Explanation:
By the second law of Newton, the force is proportional to the acceleration. If there is no force, there is no acceleration. So, when the astronaut turns off the engines, the rocket will have no acceleration which means that the speed will be constant.
Therefore, the answer is:
It will continue moving at a constant speed because no forces are acting on it.