Answer question 2!!

1. a boat is bobbing up and down on the water as waves pass underneath it. The depth of the water under the boat oscillates between 3 m and 4 m. The boat is stationary with respect to the shore and it is 2.9s between the crests of successive waves. A person on shore sees the crests of the wave passing by at 2 m/s. what is the distance between crests of this wave?

2. Two ducks are floating close together on the water near the boat in problem 1. When the first duck is on the peak of a passing wave the second duck is 30 cm below it and moving upwards. How far apart are the ducks?

Dario, a prep cook at an Italian restaurant, spins a salad spinner and observes that it rotates 20.0 times in 5.00 seconds and then stops spinning it. The salad spinner rotates 6.00 more times before it comes to rest. Assume that the spinner slows down with constant angular acceleration.

What is the magnitude of the angular acceleration of the salad spinner as it slows down?

Express your answer numerically in radians per second per second.

1

(a) How far from a 54.2 mm focal-length lens must an object be placed if its image is to be magnified 2.36? and be real?
_____ mm
(b) What if the image is to be virtual and magnified 2.36??
__________ mm

2

A diverging lens with a focal length of -14 cm is placed 14 cm to the right of a converging lens with a focal length of 18 cm. An object is placed 31 cm to the left of the converging lens.

(a) Where will the final image be located?
__________cm left of the converging lens
(b) Where will the image be if the diverging lens is 34 cm from the converging lens?
____________cm right of the diverging lens

A child slides down a hill on a toboggan with an acceleration of 1.5 m/s2.

Part A If she starts at rest, how far has she traveled in 1.0 s? Express your answer using two significant figures. dd = nothing m

Part B If she starts at rest, how far has she traveled in 2.0 s? Express your answer using two significant figures. dd = nothing m

Part C If she starts at rest, how far has she traveled in 3.0 s? Express your answer using two significant figures. dd = nothing m

A charge of -0.4 µC is located at the origin; a charge of 0.53 µC is located at x = 0.2 m, y = 0; a third charge Q is located at x = 0.32 m, y = 0. The force on the 0.53 µC charge is 4.3 N, directed in the positive x direction.

1. Determine the charge

2. With this configuration of three charges, where, along the x direction, is the electric field zero? xf=

3. x2=

Explain why it is difficult to make an X-ray laser.

What is the fastest transverse wave that can be sent along a given wire? For safety reasons, the maximum tensile stress to which this wire should be subjected is 3.56 × 108 N/m2. The density of the wire is 8300 kg/m3. Note that your answer does not depend on the diameter of the wire.

A 0.180-kg wooden rod is 1.60 m long and pivots at one end. It is held horizontally and then released.

Part A : What is the angular acceleration of the rod after it is released? Express your answer to three significant figures and include appropriate units.

Part B: What is the linear acceleration of a spot on the rod that is 0.560 m from the axis of rotation? Express your answer to three significant figures and include appropriate units.

Part C: At what location along the rod should a die be placed so that the die just begins to separate from the rod as it falls? Express your answer to three significant figures and include appropriate units.

At what radius along the perpendicular bisector of a wire of length 0.29 m carrying 30 nC of charge does the assumption of cylindrical symmetry in applying Gauss's law give you an answer whose error exceeds 5%?

Question1:playground merry-go-round has mass of 75kg and a radius of 3 m. A 25kg child sits on the merry-go-round 2/3's of way out from center.What's the moment of inertia of the merry-go-round/child system?

Question2:On the playground merry-go round in the previous question,one child pushes it CCW with a force of 20 N, while the 25 kg child drags her feet through a hole 2/3 of the way out from the center,causing a CW force of 17 N. What's angular acceleration of the merry-go-round?

Radiation from the head is a major source of heat loss from the human body. Model a head as a 21-cm-diameter, 20-cm-tall cylinder with a flat top.

If the body's surface temperature is 36?C , what is the net rate of heat loss on a chilly 9?C  day? All skin, regardless of color, is effectively black in the infrared where the radiation occurs, so use an emissivity of 0.95.

I have worked it through three times with other written solutions however i cannot arrive at the correct answer. A final answer as well as a solution would be appreciated! Thanks!

A- How much work is required to accelerate a proton from rest up to a speed of 0.995c?

W = ? J

B- What would be the momentum of this proton?

P = ? kg⋅m/s

What is the basic, fundamental meaning of the Continuity equation? What are some examples and the importance of this rule?

GOAL Apply the more general definition of torque. PROBLEM (a) A man applies a force of F = 3.00 102 N at an angle of 60.0° to the door of Figure (a), 2.00 m from the hinges. Find the torque on the door, choosing the position of the hinges as the axis of rotation. (b) Suppose a wedge is placed 1.50 m from the hinges on the other side of the door. What minimum force must the wedge exert so that the force applied in part (a) won't open the door? STRATEGY Part (a) can be solved by substitution into the general torque equation. In part (b) the hinges, the wedge, and the applied force all exert torques on the door. The door doesn't open, so the sum of these torques must be zero, a condition that can be used to find the wedge force. SOLUTION (A) Compute the torque due to the applied force exerted at 60.0°. Substitute into the general torque equation. τF = rFsin θ = (2.00 m)(3.00 ✕ 102 N) sin 60.0° = (2.00 m)(2.60 ✕ 102 N) = 5.20 102 N · m (B) Calculate the force exerted by the wedge on the other side of the door. Set the sum of the torques equal to zero. τhinge + τwedge + τF = 0 The hinge force provides no torque because it acts at the axis (r = 0). The wedge force acts at an angle of −90.0°, opposite the upward 260 N component. 0 + Fwedge(1.50 m) sin (−90.0°) + 5.20 ✕ 102 N · m = 0 Fwedge = 347 N LEARN MORE REMARKS Notice that the angle from the position vector to the wedge force is −90°. This is because, starting at the position vector, it's necessary to go 90° clockwise (the negative angular direction) to get to the force vector. Measuring the angle in this way automatically supplies the correct sign for the torque term and is consistent with the right-hand rule. Alternately, the magnitude of the torque can be found and the correct sign chosen based on physical intuition. Figure (b) illustrates the fact that the component of the force perpendicular to the lever arm causes the torque. QUESTION To make the wedge more effective in keeping the door closed, should it be placed closer to the hinge or to the doorknob? closer to the hinge closer to the doorknob PRACTICE IT Use the worked example above to help you solve this problem. (a) A man applies a force of F = 3.00 102 N at an angle of 60.0° to a door, x = 2.10 m from the hinges. Find the torque on the door, choosing the position of the hinges as the axis of rotation. N · m (b) Suppose a wedge is placed 1.50 m from the hinges on the other side of the door. What minimum force must the wedge exert so that the force applied in part (a) won't open the door? N EXERCISE HINTS: GETTING STARTED | I'M STUCK! A man ties one end of a strong rope 7.74 m long to the bumper of his truck, 0.521 m from the ground, and the other end to a vertical tree trunk at a height of 3.62 m. He uses the truck to create a tension of 7.50 102 N in the rope. Compute the magnitude of the torque on the tree due to the tension in the rope, with the base of the tree acting as the reference point. N · m