Answer:
v = 8.57 m/s
Explanation:
As we know that the wagon is pulled up by string system
So the net force on the wagon along the inclined is due to tension in the rope and component of weight along the inclined plane
So as per work energy theorem we know that
work done by tension force + work done by force of gravity = change in kinetic energy

so we have


m = 38.2 kg
d = 85.4 m
so now we have


The kinetic energy of the electron is

where

is the mass of the electron and v its speed. Since we know the value of the kinetic energy,

, we can find the value of the speed v:
Answer:
He requires 1 gram of mass.
Explanation:
The density is defined as:
(1)
Where m is the mass and V is the volume.
Then, m can be isolated from equation 1 in order to determine the mass.
(2)
Hence, he requires 1 gram of mass.