Mechanics | Relativity Answers

The coefficient of friction between the wall and the weight shown in the figure is 0.25. What force P is necessary to keep the body in place? What force P will keep the body moving up uniformly?

3.Two posts, one 8ft high and the other 12ft high, stand 15ft apart. They are to be stayed by wires attached to a single stake at ground level, the wires running to the tops of the posts. Where the stake should be placed, to use the least amount of wire?
1.At a given instant the legs of a right triangle are 8 in., and 6 in., respectively. The first leg decreases at 1 in/min and the second increases at 2 in/min. At what rate is the area increasing after 2 min.?
2.An arc light is 15 feet above a sidewalk. A man 6 feet tall walks away from the point under the light at the rate of 5ft/sec. How fast is his shadow lengthening when he is 20 feet away from the point under the light?
3.A man starts walking eastward at 5ft/sec from a point A. Ten minutes later a second man starts walking west at the rate of 5ft/sec from a point B, 3000ft north of A. How fast are they separating 10 minutes after the second man starts?

The three displacement vectors in the drawing have magnitudes of A = 4.84 m with angle of 20d.\, B = 5.35 m with angle of 60d, and C = 3.81 m with angle of 0d. Find the resultant
((a) magnitude and (b) directional angle) of the three vectors by means of the component method. Express the directional angle as an angle above the positive or negative x axis.

A mass of 0.55kg is oscillating on the end of a vertical spring. What is the the displacement of the mass when it's upward acceleration is 11.90m/s?k=140N/m

What are factors that affect the acceleration due to gravity in projectile motion?
I have a project about angry birds and but I can't find the exact acceleration due to gravity in angry birds world. I experimented, and it keeps on changing.
I m wondering whether the horizontal range is affecting it.

Also, air resistance is negligible.
Thank you in advance!!

PS: if you know how to find the acceleration due to gravity, pls help me!

10. A net torque of 36 N.m acts on a wheel rotating about a fixed axis for 6 s.
During this time the angular speed of the wheel increases from 0 to 12 rad/s. The
applied force is then removed, and the wheel comes to rest in 75 s.
a. What is the moment of inertia of the wheel?
b. What is the magnitude of the frictional torque?
c. How many revolutions does the wheel make?

7. An 80-kg man and his car are suddenly accelerated from rest to a speed of 5 m/s
as a result of a rear-end collision. Assuming the time taken to be 0.3s, find:
a) the impulse on the man and
b) the average force exerted on him by the back seat of his car.

8. An airplane propeller is rotating at 1900 rev/min.
a. Compute the propeller's angular velocity in rad/s.
b. How long in seconds does it take for the propeller to turn through 30.0
degrees?

9. A disk with a 1.0-m radius reaches a maximum angular speed of 18 rad/s before
it stops 30 revolutions after attaining the maximum speed. How long did it take
the disk to stop?

4. A 200 g mass is attached to a spring of spring constant k. The spring is
compressed 15 cm from its equilibrium value. When released the mass reaches a
speed of 5 m/s. What is the spring constant (in N/m)?

5. A 34-g bullet traveling at 120m/s embeds itself in a wooden block on a smooth
surface. The block then slides toward a spring and collides with it. The block
compresses the spring (k=100 N/m) a maximum of 1.25 cm. Calculate the mass
of the block of wood.

6. If a force of 300N is exerted upon a 60 kg mass for 3 seconds, how much
impulse does the mass experience?

a sound wave is found to have a frequency of 50Hz. Calculate the time period of the wave in seconds

Ashleigh and Bob dock a paddle boat. Ashleigh, who has a mass of 50kg moves forward at a 3.8 m/s as she leaves the boat. At what speed and in what direction do the paddle boat and bob move if their combined mass is 105kg