A person who normally weighs 700 N is riding in an elevator that is moving upward but slowing down at a steady rate. If this person is standing on a bathroom scale insidethe elevator, what would the scale read?A) more than 700 NB) less than 700 NC) 700 ND) It could be more or less than 700 N, depending on whether the magnitude of the accelerationis greater than or less than 9.8 m/s2.

B) less than 700 N

Explanation:

Given;

normal weight of the person, W = 700 N

An elevator moving upward but slowing down at a steady rate, shows that upward force is less than downward force, thus, the reading on the scale will be  less than 700 N.

Also, from Newton's second law

R - mg = ma

where;

R is the reading on the scale

mg is the weight of the person = W = 700 N

a is negative acceleration upward = -a

R - mg = -ma

R = mg - ma

Thus, If this person is standing on a bathroom scale inside the elevator, the scale will read less than 700 N.

B)  less than 700 N.

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j