In a 30.0-s interval, 500 hailstones strike a glass window of area 0.600m2 at an angle of 45.0 to the window surface. Each hailstone has a mass of 5.00 g and a speed of 8.00 m/s. Assuming the collisions are elastic,find (a) the average force and (b) the average pressure on the window during this interval.

Find the center of mass of a laminate bounded by y=−x,y=x,y=2 with variable density modeled by \rho (x,y)=y+5. Question 3 Answer a. (0,2619) b. (35,94) c. (−23,116) d. None of the above e. (0,1) f. (0,32)

An airplane has wings, each with area 3.85 m2, designed so that air flows over the top of the wing at 248 m/s and underneath the wing at 226 m/s.   Approximately what size wings would an aircraft need on Mars if its engine generates the same differences in speed as in the "Practice It" and the total mass of the craft is 300 kg? The density of air on the surface of Mars is approximately one percent Earth's density at sea level, and the acceleration of gravity on the surface of Mars is about 3.8 m/s2. ______________m2

VRMS-1 Consider a container of Argon gas at a temperature of 25.0 °C. The mass of an Argon atom is 39.96 AMU, where 1 AMU = 1.66×10-27 kg. (a) What is the average kinetic energy per Argon atom, in Joules (J)? (b) What is the RMS average speed of the Argon atoms, in meters per second (m/s)? (c) What would the temperature of the gas have to be for the RMS average speed to 275 m/s? Give your answer in degrees Celsius (°C).

In a period of 0.9 s, 5.0  1023 nitrogen molecules strike a wall of area 7.6 cm2. If the molecules move at 320 m/s and strike the wall head on in a perfectly elastic collision, find the pressure exerted on the wall. (The mass of one N2 molecule is 4.68  10-26 kg.)

A uniform disk of mass 10.0 kg and radius of 0.248 m spins at 302 rev/min on a low-friction axle. It must be brought to a stop in 1.00 min by a brake pad that makes contact with the disk at an average distance of 0.218 m from the axis. The coefficient of friction between the pad and the disk is 0.499. A piston in a cylinder of diameter 5.00 cm presses the brake pad against the disk. Find the pressure required for the brake fluid in the cylinder. Pa Need Help? Read It

Superman leaps in front of Lois Lane to save her from a volley of bullets. In a 1-minute interval, an automatic weapon fires 150 bullets, each of mass 8.0 g, at 400 m/s. The bullets strike his mighty chest, which has an area of 0.75 m2. Find the average force exerted on Superman’s chest if the bullets bounce back after an elastic, head-on collision.

A cylinder is fitted with a piston, beneath which is a spring, as in the drawing. The cylinder is open to the air at the top. Friction is absent. The spring constant of the spring is 3600 N/m. The piston has a negligible mass and a radius of 0.010 m. (a) When the air beneath the piston is completely pumped out, how much does the atmospheric pressure cause the spring to compress? (b) How much work does the atmospheric pressure do in compressing the spring?   * I know that a is = 0.0088422743 m  but b is NOT 8.950712099 J (wrong) please show work of how to work part b.

A hand-driven tire pump has a piston with a 2.1 cm diameter and a maximum stroke of 24 cm. (a)  How much work do you do in one stroke if the average gauge pressure is 2.1 × 105 N/m2?  (b)  What average force do you exert on the piston, neglecting friction and gravitational force?

Water is ejected from the water nozzle with a speed vo = 41.7 ft/sec. For what value of the angle will the water land closest to the wall after clearing the top? Neglect the effects of wall thickness and air resistance. What distance x to the right of point B does the water land? Answer: 0 = A X= 10 8 13.3' i i 45' Not to scale ft 6.9' B