Physics Answers

1. Shaniya and Maxine move a box of toy with a mass of 20 kg from an initial position to one that is 8 m away towards the right. Shaniya on the left of the box pushes the box with a force of 5 N at an angle of 10? downward from the horizontal while Maxine on the right of the box pulls it with a force of 5 N 200 abovethe horizontal. The forces exerted by both girls are constant. What is the net work (Wnet) the two girls exert on the box?

On the + y axis a laser is located at y = + 3.0 cm. The coordinates of a small target are x = + 12.0 cm and y = + 6.0 cm. The + x axis represents the edge-on view of a plane mirror. At what point on the + x axis should the laser be aimed in order for the laser light to hit the target after reflection?

Question 10 options:

A)

+4 cm

B)

+3 cm

C)

-3 cm

D)

- 4 cm

You place an object 22 cm in front of a concave lens with a focal length of -35 cm. Find the image distance and magnification that results from this arrangement.

You place an object 22 cm in front of a concave lens with a focal length of -35 cm. Find the image distance and magnification that results from this arrangement.

Assume 2 kg of hydrogen (Item B 28) are initially at 40 atm, 100 K. (a) If the hydrogen changes pressure to 1 atm without a change of temperature, find the changes of enthalpy and entropy. (b) If the hydrogen changes temperature to 35 K with no change of entropy, find the change of pressure and enthalpy.

Postulate of Bohr Atomic Model

What is Bohr atomic model

5. Kilauea in Hawaii is the world’s most continuously active volcano. Very active volcanoes characteristically eject red-hot rocks and lava rather than smoke and ash. Suppose a large rock is ejected from the volcano with a speed of 25.0 m/s and at an angle 35.0º above the horizontal. The rock strikes the side of the volcano at an altitude 20.0 m lower than its starting point.

a. Calculate the time it takes the rock to follow this path.

b. What are the magnitude and direction of the rock’s velocity at impact?

1. If an arrow is fired from a bow with a perfectly horizontal velocity of 60.0 m/s and the arrow was 2.00 m above the ground when the it was released, how far will the arrow fly horizontally before it strikes theground?

2. A rock was thrown horizontally from a 100.0 m high cliff. It strikes the ground 90.0 m from the base of the cliff. At what speed was it thrown?

3. A cliff diver running 3.60 m/s dives out horizontally from the edge of a vertical cliff and reaches the water below 2.00 s later. How high is the cliff and how far from the base of the cliff did the diver hit the water?

4. During a fireworks display, a shell is shot into the air with an initial speed of 70.0 m/s at an angle of75.0º above the horizontal. The fuse is timed to ignite the shell just as it reaches its highest point above the ground.

a. Calculate the height at which the shell explodes.

b. How much time passed between the launch of the shell and the explosion?

c. What is the horizontal displacement of the shell when it explodes?

A liker walk 53.1 degree north of east for 2.5km then due east for 2km. What is her total displacement from her starting point if you measure the distance along straight line?