Physics Answers

The fan blades are rotating with an angular speed of -120 rad/s . As the plane takes off, the angular velocity of the blades reaches -390 rad/s in a time of 19s. Find the angular acceleration, assuming it to be constant.

If a cyclist is traveling along a road due East at 10km/h and a wind is from South West at 3km/h .Find the velocity of the wind relative to the cyclist

A flat circular disk of radius "a" is placed inside a uniform external electric field E' pointing in positive z direction. calculate the net electric flux through the disk.

Express /phi/ of spherical coordinates in terms of  Cartesian Unit vectors. 

A 2-kg steel ball is attached to the end of a flat strip of metal that is clamped at its base. If the spring constant is 8 N/m, the frequency of vibration will be approximately?

a 60kg man on a 3kg stretcher that is 2.6m long. his center of mass is 1m from one end. how much force must be entered to keep horizontal

1) A 96.9-J work is done on spring by stretching it a distance of 13.6cm. How much energy (in J) is stored in the spring?

Select one:

a. 96.90

b. 1317.84

c. 7.13

d. 83.30

2) A block of mass 8.7-kg sits on a frictionless table and is connected to a horizontal spring whose spring constant is 68.4-N/m. The block is moved to compress the spring by a distance of 5.1-cm before releasing the system from rest. Determine the maximum speed of the block.

3) A concrete block with a mass of 7.7-kg was accidentally dropped by a worker at a construction site from a scaffold which is 21-m above the ground. Calculate how much gravitational potential energy the block possesses after falling half the distance. Ignore the effects of air resistance.

Select one:

a. 1585 J

b. 792.330 J

c. 162 J

d. 80.85 J

1) What is the momentum of a cyclist with a total mass (bike + rider) of 78.3kg moving with a velocity of 19.4m/s?

 2) Ten seconds after an electric fan is turned on, the fan rotates at 7.3rev/min. Its average angular acceleration is:

Select one:

a. 0.076

b. 0.01

c. 0.04

d. 4.59

e. 0.76 

3) A 124.6-kg object is dropped from a height of 3.8m above a spring with a constant of 14235.8N/m. How much (in cm) will the spring be compressed?

1.If a wheel is turning at 7.7rad/s, the time (in seconds) it takes to complete one revolution is about:

Select one:

a. 0.82

b. 2.5

c. 48

d. 24

e. 0.41

2.A flat (unbanked) curve on a highway has a radius of 222.8m. A car rounds the curve at a speed of 27.6m/s. What is the minimum coefficient of friction that will prevent sliding?

3.Suppose a stationary 52.5-kg box is on top of your table. What is the work done by gravity?

Select one:

a. 52.50 J

b. 0 J

c. 9.8 J

d. 514.50 J

1. A golf ball of mass 0.04kg hit off the tree at a speed of 40.5 m/s. The golf club was in contact with the ball for 0.003s. Find the average force exerted on the ball by the golf club.
2. A golf ball of mass 0.08kg hit off the tree at a speed of 38m/s. The golf club was in contact with the ball for 0.003s. Find the impulse imparted to the golf ball.
3. A flywheel is initially rotating at 5.9 rad/s and has a constant angular acceleration. After 3s it has rotated through 30 rad. The magnitude of its angular acceleration in rad/s² is: