Physics Answers

The height of a cylindrical tank, containing 15 lb of gas at 70 psia and 115o F is triple its diameter; the gas constant R = 45 ft-lb/lboR. Find the tank height. 

What is the mass of the air contained in a room 6m X 5m x 4m if the pressure is 100 kPa and the temperature is 25oC

How Electromagnetic Waves behave in...

Vacuum?

Optical Medium?

A calesa pulled by a horse carries a 75.0-kg load containing copies of modules to be distributed in remote barangays. The calesa has a mass of 2.50 x 103 kg. If the calesa moves accelerates at a rate of 4.00 m/s2 , how much pull was exerted by the horse? 

A person is jumping from a height ℎ0 = 10 m with zero initial velocity and a cricket ball is thrown directly upward with an initial velocity 𝑣𝑣0 = 9.8 m/s at the same instant when time t = 0 s as shown in Fig. 1. Consider h = 11.5 m and 𝚤𝚤̂and 𝚥𝚥̂ to be the unit vectors along the X and Y axis. Gravity is acting along the -𝚥𝚥̂direction and the magnitude of gravitational acceleration is given by g = 9.81 m/s2 . The red dot on the person represents his center of mass.

(a) (4 marks) If the person and the cricket ball consist of a system, find the position and velocity of the center of mass of the system at time t = 0.5 s.

(b) (2 marks) If it takes 0.01 seconds for the person to come to complete rest when he hits the ground, calculate the average force acting on the person.

(c) (4 marks) Now consider when the person hits the ground, he bends his knees such that the center of mass of his body is lowered by 15 cm. If the maximum force that the bone of his legs can withstand is 50000 N, will he break his legs?

2. At a sharp horizontal circular turn a train slows down going from 90.0 km/h to 50.0 km/h in the 15.0 s it takes to round the bend. The radius of the curve is 150 m. Assume the train continues to slow down at the same rate. At the moment the train speed reaches 50.0 km/h calculate:

(a) (3 marks) the magnitude and direction of the tangential acceleration.

(b) (3 marks) the radial acceleration (magnitude and direction).

(c) (4 marks) the magnitude and direction of the total acceleration.

An astronomical telescope has an angular Magnification of 40 times. If the diameter of the obejective is 12cm and the length of the tube is 1m, calculate the focal length of the objective and tbe diameter of the exit pupil.

Given that the moon has about has the same angular size as the new 20 peso coin, held at 1m from the eye and that the diameter of the moon is 3.5 x 10^6 m estimate the distance from the earth to the moon.

Two trains A and B are moving towards each other at a speed of 156.2m/s. If the frequency of the whistle emitted by A is 844.6Hz, then what is the apparent frequency of the whistle heard by the passenger sitting in train B. Note that the velocity of sound in air is 340m/s.

3. Each croquet ball in a set has a mass of 0.50 kg. The green ball, traveling at 12.0 m/s, strikes the blue ball, which is at rest. Assuming that the balls slide on a frictionless surface and all collisions are head-on, find the final speed of the blue ball in each of the following situations:

a. The green ball stops moving after it strikes the blue ball.

b. The green ball continues moving after the collision at 2.4 m/s in the

same direction.

c. The green ball continues moving after the collision at 0.3 m/s in the

same direction.