A35 kg box is pulled with a rope from above at an angle of 20. the box begins to move when f 200n. calculate the frictional force acting on the box. calculate the normal force acting on the box.

b) 188 N

c) 275 N

Explanation:

Draw a free body diagram of the box.  There are four forces:

Applied force F at an angle θ

Weight mg pulling down

Normal force Fn pushing up

Friction force Ff pushing left

(b)

Sum of the forces in the x direction:

∑F = ma

F cos θ − Ff = 0

Ff = F cos θ

Ff = 200 cos 20°

Ff = 188 N

(c)

Sum of the forces in the y direction:

∑F = ma

F sin θ + Fn − mg = 0

Fn = mg − F sin θ

Fn = (35)(9.8) − 200 sin 20°

Fn = 275 N

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: