Alex is asked to move two boxes of books in contact with each other resting on a rough floor. he decides to move both of them at the same time by pushing on box a with a horizontal pushing force of fp=8.9 n. here a has a mass of ma= 11.0 kg and b has a mass of mb= 7.0 kg. the contact force between the two boxes is fc. the coefficient of kinetic friction between the boxes and floor is .02. (assume fp acts in the +x direction)

a) what is the magnitude of the acceleration of the two boxes? m/s^2

b) what is the force exerted on mb by ma. in other words what is the magnitude of the contact force fc? n

c) if alex were to push from the other side on the 7.0 kg box, what would the new magnitude of fc be?

Aseries circuit consists of a resistor with r = 20 ? , a capacitor with c = 0.01 f, and a decaying battery with e = 300e? 5t. if the initial charge is 0, find the charge as a function of time t

3. a worker pushes a 30.5 kg polished stone along a polished table with a force on bonin a straight line for 5.20 s after starting from rest. there is no friction between thestone and the table. at the end of the table. the stone is hooked to a cable with a lengthof 62.0 cm to rotate it to a rough table to store until they can be picked up. the roughtable has a coefficient of static friction 0.702 with the polished stone. remember that 8= 9.80 m/s2a) what is the speed of the stone when it is hooked to the cable? b) what is the tension in the cable while the stone is rotating? (there is still nofriction)c) how much force is needed to make the stone begin sliding from rest on therough table? ius = 0.70262.0 cm30.5 kg20.5 kg6= 0

How many astronauts have walked on the moon?