Answer:
I think its A plz tell me if im right
Density formula: d = M/V
So I think the answer would be 5.67/ 835 I am not sure of the answer I got confused (´∀`) but I hope it will help
Answer:

Explanation:
It is given that, a proton moves at constant velocity, through a region in which there is an electric field and a magnetic field such that,
The electric field is, E = 800 V/m
Magnetic field, B = 0.25 T
We know that the net force in the region of magnetic and electric field is given by Lorentz forces. But here, the proton moves with constant velocity. So, the net force acting on it is 0.
i.e.

Hence, this is the required solution.
Kinetic Energy = (1/2) (mass) (speed)
First runner: KE = (1/2) (45kg) (49 m/s) = 1,102.5 Joules
Second runner: KE = (1/2) (93kg) (9 m/s) = 418.5 Joules
The <em>first runner </em><em>has 163</em>% more kinetic energy than the second runner has.