Ashopper in a supermarket pushes a cart with a force of 35.0 n directed at an angle of 25.08 below the horizontal. the force is just sufficient to balance various friction forces, so the cart moves at constant speed. (a) find the work done by the shopper on the cart as she moves down a 50.0-m-long aisle. (b) the shopper goes down the next aisle, pushing horizontally and maintaining the same speed as before. if the friction force doesn’t change, would the shopper’s applied force be larger, smaller, or the same? (c) what about the work done on the cart by the shopper?

a)1585 J

b)The applied force would be smaller and the work would again be zero

c)0 N

Explanation:

a)  The horizontal component of the applied force is 35 N x cos 25.08 = 31.70 N

Work = force x distance = 31.7 N x 50 m = 1,585 J

b)  If the applied force were horizontal, all of it would counter friction, so only 31.7 N would be needed.  The work done on the cart is zero because there is no change in mechanical energy.

c) The work done on the  cart by the shopper will be zero because there is no change in mechanical energy.

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: