A scientist looking for meteorites on Antarctica

finds an irregularly shaped rock and

he wants to determine its density. He determines that the rock’s mass in air is 50

kg.

The Young’s modulus of steel is 200

·

10

9

Nm

-

2

. The ultimate strength of steel is

500

·

10

6

Nm

-

2

.

Q 4(a)

[5

Marks]

He hangs the rock from a

2

-

metre

-

long

steel cable with a diameter of 1

cm. Calculate

the strain and change in length of the cable

.

Q 4(b)

[5 Marks]

What would happen if he had used a cable with a diameter of only 2mm? Explain

your answer.

Thescientist now submerges the rock in a tub of water. He now determines the effective weight to be 38.5kg.

Q 4(c)

[5

Marks]

Calculate the volume and density of the rock

.

Q 4(d)

[5 Marks]

If the scientist had used alcohol (ρ=789kg/m3), would he have found a larger or smaller effective weight when the rock is submerged?

Explain your answer.

draw hertzsprug russell diagram for an open star cluster and a globular cluster and discuss the differences

A laser emits a cylindrical beam of light 4.0 mm in diameter. The average power of the laser is 2.8 mW . The laser shines its light on a perfectly absorbing surface.

How much energy does the surface receive in 14 s ?

What is the radiation pressure exerted by the beam?

The most common isotope of boron is 115B.

part b) Calculate this binding energy from equation EB=C1A−C2A2/3−C3Z(Z−1)/A1/3−C4(A−2Z)2/A±C5A−4/3. Express your answer using four significant figures. (in MeV)

part c) Why is the fifth term zero?

A quarterback throws a pass that is a perfect spiral. In other words, the football does not wobble, but spins smoothly about an axis passing through each end of the ball. Suppose the ball spins at 6.3 rev/s. In addition, the ball is thrown with a linear speed of 29 m/s at an angle of 45 ° with respect to the ground. If the ball is caught at the same height at which it left the quarterback's hand, how many revolutions has the ball made while in the air?

State the Three Laws of Thermodynamics (2nd Law has multiple parts).

Two beams of electrons, beam 1 and beam 2, are moving along straight lines perpendicular to the page. We take the page to be the xy-plane. Beam 1 is moving into the page and intersects the page at point (−2, cm, 0 cm). Beam 2 is moving out of the page and intersects the page at point (2, cm, 0 cm). The streams of electrons are otherwise identical, each carrying current of magnitude 2 A. A negatively-charged particle having charge three times that of an electron is at point (x,y) = (0cm,2cm) and has velocity (vx , vy ) = (5 × 103 m/s, −5 × 103 m/s). What is the magnitude and direction of the net magnetic force on the negatively-charged particle due to the pair of electron beams?

A wire carries an I₁ = 7.85-A current along the x-axis, and another wire carries an I₂ = 5.85-A current along the y-axis, as shown in the figure below. What is the magnetic field at point P, located at x = 4.00 m, y = 3.00 m?

#4. A vase was placed on the coffee table. The coefficient of static friction between the vase and the table is 0.3689, whereas the coefficient of kinetic friction is 0.1339. The vase weighs 1.0707kg. A cat decided to redecorate the room by pushing the vase off the table. As the cat pushes the vase with its paw, the vase moves. Then, the cat maintains a constant applied force of 7.37N on the vase in the positive x-direction. What is the acceleration of the vase in the x-direction during the time when the vase is moving?

#6. A student has two springs. Spring 1 is twice the mass of spring 2. The student first puts spring 1 into a massless pouch and suspends it from spring 2. Spring extension was noted to be 12.69cm. Then, they put spring 2 into a massless pouch and suspend it from spring 1. Spring extension was noted to be 16.42cm.
What is the ratio of k1/k2?

A hockey puck (1) of mass 130 g is shot west at a speed of 8.40 m/s. It strikes a second puck (2), initially at rest, of mass 124 g. As a result of the collision, the first puck (1) is deflected at an angle of 32° north of west and the second puck (2) moves at an angle of 40° south of west. What is the magnitude of the velocity of puck (1) after the collision?

a) If an atom has an electron in the n=3 state with m=1, what are the possible values of l, the angular momentum quantum number?

b)What are the possible values of m for an electron in the n=3 state?

Does a flat mirror produce a real or virtual image? What is its magnification?

A block of mass m1=4.00 kg moves on the surface of a horizontal table. The coefficient of kinetic friction between the table top and m1 is equal to 0.350. Block 2 of mass m2=2.00 kg is tied to m1 via a string that passes over a frictionless, massless pulley. The two blocks start from rest and m2drops by a distance L=1.75 m to the floor.

Calculate the net work Wnet done by all the forces acting on the system

An object that weighs 1180 N rests on a lever at a point 0.370 m from a support. On the same side of the support, at a distance of 3.00 m from it, an upward force with magnitude F is applied. Ignore the weight of the board itself. If the system is in equilibrium, what is F? Express your answer in Newtons. where P = 1180 and x = 0.370. N