# The tub of a washing machine goes into its spin cycle, starting from rest and gaining angular speed steadily for 6.00 s, at which time it is turning at 4.00 rev/s. At this point, the lid of the washing machine is opened, and a safety switch turns it off. The tub then smoothly slows to rest in 15.0 s. Through how many revolutions does the tub rotate while it is in motion?_____________ rev

Explanation:

As we know that initial angular speed of the tub was zero and then it increases uniformly to 4 rev/s in t = 6.00 s

so we will have

Now when the tub will comes to rest uniformly after opening the lid in time interval of t = 15 s

then we have

Now total angular displacement of the tub is given as

so number of revolutions is given as

## Related Questions

Which of the following is sometimes called electrical potential? A. ohms
B. amps
C. voltage
D. resistance

C. Voltage.

Voltage is sometimes called electrical potential.

A pendulum of length l is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is t. How does the period of the pendulum change when the elevator moves downward with constant acceleration?

The period of the pendulum will increase.

Explanation:

The period of the pendulum will increase since g efective will decrease.

Then g efective is given by

g efective = g - a < g

If ⇒  T = 2π√(L/g)

and T' = 2π√(L/(g - a))

then  T < T'

When the elevator accelerates downward, the hanging mass  feels “lighter” – this means that the effective value of g has  decreased due to the acceleration of the elevator. Since the  period depends inversely on g, and the effective value of g  decreased, then the period of the pendulum will increase .

(i.e., its frequency will decrease and it will swing slower)

The distance between the centers of the wheels of a motorcycle is 146 cm. The center of mass ofthe motorcycle, including the rider, is 78.5 cm above the ground and halfway between the wheels.Assume the mass of each wheel is small compared to the body of the motorcycle. The enginedrives the rear wheel only. What horizontal acceleration of the motorcycle will make the frontwheel rise off the ground

9.12267515924 m/s²

Explanation:

Here the moment created by the wheels and the moment created by the center of gravity will balance each other.

h = Height of the center of mass = 78.5 cm

d =  Distance from back wheel to the center of mass =

g = Acceleration due to gravity = 9.81 m/s²

a = Horizontal acceleration

The equation is of the form

The horizontal acceleration of the motorcycle that will make the front wheel rise off the ground is 9.12267515924 m/s²

Determine the moment about the origin O of the force F=(13)i + (-12)j + 14(k) that acts at a point A. Assume that the position vector of A is r=2i+3j-4k. The moment about the origin of the force F is ()i+()j+()k