<span>Yes, there are! r1 and r2 are numbers. The volume of the hollow shell is 4 π 3 ( r 3 1 − r 3 2 ) 4π3(r13−r23). Now multiply by ρ to get the mass.</span>
Answer:
The elevator must be <u>accelerating upward</u> as the net force acting is upward.
Explanation:
Given:
Original weight of the student, 
Reading on the spring scale is the normal reaction by the scale on the student and is given as, 
The normal reaction acts in the upward direction while the weight of the student acts vertically downward.
Now, the magnitude of the normal reaction is greater than the magnitude of the weight. Therefore, the net force acting on the student is given as:

Therefore, the net force is acting vertically upward.
Now, as per Newton's second law, the direction of the net acceleration acting on a body is the same as the direction of the net force acting on it.
Thus, the elevator must be accelerating upward as the net force acting is upward.
Answer:
pulling force
Explanation:
because the person is pulling that cart.
Answer:
30 kilometers is a reasonable measurement
Answer:
a) the number of particles increases
b) average distance between them should decrease
c) the number of particles decreases, the pressure must also decrease
Explanation:
a) When the girl pumps to increase the pressure inside the tire she introduces more particles. Therefore the number of particles increases
b) as the volume of the tire does not change and there are more particles, the average distance between them should decrease
c) When a hole is opened, some of the particles inside the tire come out, so as the number of particles decreases, the pressure must also decrease