Physics Questions and Answers January 22, 2020

As a first approximation the Earth is considered as a sphere of average radius R - 6370km. This neglects a bulge at the equator, flattening at the poles, and local irregularities. What fraction of the Earths radius is the tallest mountain? The depth of the deepest ocean trench? The average ocean depth? Does your result mean that one can treat the

The wheel and the attached reel have a combined weight of 50 lb and a radius of gyration about their center of kA = 6 in. If pulley B that is attached to the motor is subjected to a torque of M 50 lb*ft. determine the velocity of the 200-lb crate after the pulley has turned 5 revolutions. Neglect the mass of the pulley.

7.5 in. 4.5 in. 3 in. M

The spool has a mass of 50 kg and a radius of gyration k0 = 0.280 m. If the 20-kg block A is released from rest, determine the velocity of the block when it descends 0.5 m.

Determine the speed of the 50-kg cylinder after it has descended a distance of 2 m. starting from rest. Gear A has a mass of 10 kg and a radius of gyration of 125 mm about its center of mass. Gear B and drum C have a combined mass of 30 kg and a radius of gyration about their center of mass of 150 mm.

The assembly weighs 10 lb and has a radius of gyration kC/ = 0.6 ft about its center of mass G. The kinetic energy of the assembly is 31 ft lb when it is in the position shown. If it rolls counterclockwise on the surface without slipping, determine its linear momentum at this instant.

The amusement park ride consists of two gondolas A and 5. and counterweights C and D that swing in opposite directions. Using realistic dimensions and mass, calculate the angular momentum of this system for any angular position of the gondolas. Explain through analysis why it is a good idea to design this system to have counterweights with each

A thin rod is initially coincident with the Z-axis when it is given three rotations defined by the Euler angles 4> = 30. 0 = 45. and / = 60. If these rotations are given in the order stated, determine the coordinate direction angles a, (3. y of the axis of the rod with respect to the X. Y. and Z axes. Are these directions the same for any order

You have seen a tennis ball, a cricket ball, an orange and a pumpkin. Which one amongst these resembles the shape of the earth? Why have you chosen this particular item to describe the shape of the earth?

A bird is tossing (flying to and fro) between two cars moving towards each other on a straight road. One car has a speed of 18 m/h while the other has the speed of 27km/h. The bird starts moving from first car towards the other and is moving with the speed of 36km/h and when the two cars were separated by 36 km. What is the total distance covered

Rub a comb through your hair and use it to lift pieces of paper. It may help to tear the pieces of paper rather than cut them neatly. Repeat the exercise in your bathroom after you have had a long shower and the air in the bathroom is moist. Is it easier to get electrostatic effects in dry or moist air? Why would torn paper be more attractive to

Suppose a 2 million kg meteor is initially basically at rest in the asteroid belt, at a distance of 4.0 x10 km from the Sun. As it falls toward the sun it collides with the Earth (ending up 1.5 x 108 km from the Sun). a) What is its Kinetic Energy at impact (Assume throughout that only the gravity of the Sun matters). b) Compare your result with

(c) What will the direction of polarisation of the transmitted light be in (b) Give the direction in terms of an angle relative to the horizontal. (d) The polariser is rotated so that its transmission axis is vertical, 90 from the horizontal. Describe what now happens to the horizontally polarised light that strikes it. ,Sunlight is incident on a

Light from a green laser, with a wavelength of 510 nm, is shone through a single slit with a width of 1.2 cm and onto a screen placed some distance behind. (a) Which of the following most closely resembles the pattern you would expect to see on the screen A marks Answer 1 (b) Justify your choice by briefly explaining what kind of model of light

A 0.80kg block slides on a horizontal surface and collides with one end of a horizontal spring (spring constant 50 Nm) where the other end of the spring is fixed to a wall. The speed of the block just as it collides with the uncompressed spring is 1.0 ms. The block then compresses the spring by a maximum amount of 0.10 m. (a) What is the net work