Answer:
The average velocity is 40km/h.
Explanation:
The average velocity is
, where
is the distance traveled and
the time elapsed.
The distance traveled is clearly 80km since it's all done in the same direction, we only need to know the time elapsed. For this we calculate the time elapsed on the first part, and add it to the time elapsed on the second part using always the formula
, where v is the velocity on each part, which is constant.
The time elapsed for the first part is
, and the time elapsed for the second part is
, giving us a total time of
=2h.
Finally, we can calculate the average velocity:
.
Answer:
option B
Explanation:
Radius of new planet,R' = 2R
Mass of the earth, M' = 2 M
R and M is the Radius and Mass of the earth.
Weight of the person on earth = 500 N
Weight of the person in the new planet = ?
We know acceleration due to gravity is calculated by using formula

now, acceleration due to gravity on the new planet




here acceleration due to gravity is half in new planet, so weight will also be half on the new planet.
Weight on the new plane is equal to
= 250 N
correct answer is option B
False because friction will generate heat energy and/or sound energy etc. Think of a car stopping or a broom sweeping the ground.
The mass of Laura and the sled combined is 887.5 kg