Answer:
Distance - 1000m
Time - 20min
Speed - ?
Use the formula of distance ÷ time = speed.
s = d/t
s = 1000m/20min
s = 50 m/min
Hope this helps, thank you !!
Answer:

Explanation:
If m is the mass of the object and v is the velocity of the object. The kinetic energy is due to the motion of an object. It is given by the relation as follows :

The above formula is used to find the kinetic energy of an object.
I'm going to have to go with A Magnetic because it seems to be the only one that makes sense it can't B because electron and Electrical are the same thing its not going deflect it and C it might seem right but gravity has nothing to do with deflection so I pick Magnetic.
So your answer is A.
efficiency of heat engine is given as

now we know that
= temperature of sink
= temperature of high temperature source
now it is given that


now from the given equation we have


so efficiency of heat engine will be 78%