F=mass x acceleration = ma= 0.8*20 = 16N
<span>I believe this question has additional detail which stated
that during the 1st half, his speed was 2.01 m/s. From this we can
calculate his speed during the second half, v2, using the formula:</span>
v_ave = (v1 + v2) / 2
2.05 m/s = (2.01 m/s + v2) / 2
<span>v2 = 2.09 m/s</span>
Answer:
2.5 x 10^-3 T
Explanation:
n = 100 turns / cm = 10000 turns / m, R = 60 ohm, V = 12 V
i = V / R = 12 / 60 = 0.2 A
Magnetic field due to solenoid is
B = μ0 x n x i
B = 4 x 3.14 x 10^-7 x 10000 x 0.2
B = 2.5 x 10^-3 T
Use the formula,

to answer. We need the Mass, which is weight divided by acceleration. So, let's solve for F (force):

Plug in known values:

Solve:

Then, since we need mass, assuming we are on Earth, and there are no neutron stars, or anything like that close by, we can divide the weight by acceleration of gravity (9.8 m/s^2) to get the mass:

Simplify:
B. Density. I hope this helps!