An elevator is accelerating upward at a rate of 3.8 m/s2. A block of mass 24 kg hangs by a low-mass rope from the ceiling, and another block of mass 63 kg hangs by a low-mass rope from the upper block.

(a) What are the tensions in the upper and lower ropes?

upper rope N
lower rope N
(b) What are the tensions in the upper and lower ropes when the elevator accelerates downward at a rate of 3.8 m/s2?

upper rope N
lower rope N

The consumption of fossil fuels could be

A1,700kg car is being used to give a 1,400kg car a push start by exerting a force of 140n the impulse on the smaller car during the 30.0s of contact is +670kg*m/s. what is the impulse of the smaller car on the larger car? -814 kg*m/s 0kg *m/s -670kg*m/s -550kg*m/s

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.