Answer:
The linear speed of the car, v, is 24.26 m/s
Explanation:
Given;
radius of the car's tire, r = 0.330 m
angular speed of the car, ω = 11.7 revolutions/s
The angular speed of the car in radian per second:

The linear speed of the car, v, is calculated as;
v = ωr
v = 73.523 rad/s x 0.33 m
v = 24.26 m/s
Therefore, the linear speed of the car, v, is 24.26 m/s
It is incorrect to say heavy objects sink in water because based on the density of the water it can actually cause the "heavy object" to float, out weighing it.
This is in the thermosphere which is at an altitude of 85-520km
Answer:
The amount of current that must flow through the wire for it to be suspended against gravity by magnetic force = 6.125 A
Explanation:
Force on a wire carrying current in an electric field is given by
F = (B)(I)(L) sin θ
For this question,
The magnetic force must match the weight of the wire.
F = mg
mg = (B)(I)(L) sin θ
(m/L)g = (B)(I) sin θ
Mass per unit length = 75 g/m = 0.075 kg/m
B = magnetic field = 0.12 T
I = ?
g = acceleration due to gravity = 9.8 m/s
θ = angle between wire's current direction and magnetic field = 90°
0.075 × 9.8 = 0.12 × I sin 90°
I = 0.075 × 9.8/0.12 = 6.125 A