Answer:
When the elevator is accelerating downward, the person feels lighter due to the downward normal force being less than the person's weight.
Explanation:
A person riding in an elevator subjected to a series of unbalanced forces depending on the direction the elevator is travelling.
Two forces are acting on the person; the force of gravity and the upward normal force from the elevator.
When the elevator is going upwards with acceleration a, the person feels heavier than his normal weight, due to the upward normal force being greater than the person's weight. N = mg + ma
When the elevator is moving downwards with acceleration a, the person feels lighter due to the downward normal force being less than the person's weight. N = mg - ma
However, when the elevator is moving up or down at constant velocity ie. acceleration a = 0, the person experience a normal force equal to weight. N = mg
When the elevator is moving downwards with acceleration a = g, the person experiences weightlessness. N = (mg - mg) = 0
Answer:
3.014 x 10⁻⁸ N
Explanation:
q = magnitude of charge on the supersonic jet = 0.55 μC = 0.55 x 10⁻⁶ C
v = speed of the jet = 685 m/s
B = magnitude of magnetic field in the region = 8 x 10⁻⁵ T
θ = angle between the magnetic field and direction of motion = 90
magnitude of the magnetic force is given as
F = q v B Sinθ
F = (0.55 x 10⁻⁶) (685) (8 x 10⁻⁵) Sin90
F = 3.014 x 10⁻⁸ N
The density of gold is 2.8 N / 15 = 0.18 units
The density of mercury is 0.13/1 = 0.13 units
Since the density of gold is more than density of mercury, it will sink.
Since the gold will sink, it will displace mercury, but less than its own volume
