How dangerous is radioactivity? Discuss the real and imagined dangers. Give examples, along with numbers. Which risks are known from direct observation, and which are known only from calculations? What assumptions are made in calculating risk?

a) What is the relation between incline angle (0 degrees being flat, and 90 degrees being a vertical incline) and acceleration along the incline when friction is not involved?

g*(1-cos(theta)^2); g*sin(theta); g*(1-cos(theta)) or g*cos(theta)

b) When an object is on an incline, what is the relation between the objects weight and the normal force?

m*g*cos(theta); m*g*sin(theta); m*g*(1-cos(theta)) or m*g*(1-cos(theta)^2)

c) What is the force required to make an object under static friction begin motion?

a. the normal force times the coefficient of static friction

b. the normal force times the coefficient of kinetic friction

c. the force due to gravity times the coefficient of kinetic friction

d. mass times the coefficient of static friction

d) What is the relation between the coefficient of kinetic friction and the angle of inclination required to make an object have a constant velocity (no acceleration) going down an incline?

g*m*cos(theta); g*m*cos(theta) - N; tan(theta) or g*(1-cos(theta)^2)

e) The small angle approximation states that sin(theta) can be approximated as what when the angle, theta, is small?

theta in degrees; 1 - theta in radians; 1; or theta in radians

You have a 200 Ω resistor, a 0.400-H inductor. Suppose you take the resistor and inductor and make a series circuit with a voltage source that has voltage amplitude 30.0V and an angular frequency of 250 rad/s.

Parts A, B, C
For this R-L circuit graph v, vR, and vL versus t for t = 0 to t = 50.0 ms. The current is given by i=Icosωt, so v=Vcos(ωt+ϕ).

Part D
What are v, vR, and vL at t = 20.0ms?
Enter your answers numerically separated by commas.

v,vR,vL v , v R , v L = ?, ?, ? V

Part F
What are v, vR, and vL at t = 40.0ms?
Enter your answers numerically separated by commas.

v,vR,vL v , v R , v L = ?, ?, ? V

a ferris wheel 42.5m in diameter rotates once every 18.2s. What is the ratio of a person's apparent weight to her real weight at (a) the top and (b) the bottom?

please please PLEASE show all steps and write out all the work I have been stuck on this problem and I can't figure out where I'm going wrong.

Do all objects in free fall reach terminal velocity because I thought objects in free fall always accelerate with 9.8 m/s/s so why is there a point where they stop accelerating

A 7.50g bullet traveling at 490m/s embeds itself in a 1.59kg wooden block at rest on a frictionless surface. The block is attached to a spring with k = 89.0N/m

Find the Period

Find the amplitude of the subsequent simple harmonic motion.

A 22 g ball with a radius of 29 mm rolls back and forth in a hemispherical bowl of radius 6 cm.

(a) What is the period of the oscillation if the ball is solid?


(b) What is the period of the oscillation if the ball is hollow?


(c) What is the percent difference between the two?

Two objects are moving in the xy-plane. The first, with mass 2.8 kg, has a velocity v₁ = (-2.0 m/s) i + (-3.5 m/s) j; the second object, with mass 1.5 kg, has velocity v₂ = (2.1 m/s) i + (-1.5 m/s) j.

(a) What is the total momentum of the system?
( -2.45 i + -12.05 j) kg·m/s

(b) If the system observed at a later time shows that the 2.8 kg object has v'₁ = (2.0 m/s) i, what is the velocity of the 1.5 kg object?
( ? i + ? j) m/s

(c) Consider again the initial situation. Now suppose that there has been a mass transfer, so that the first object now has a mass of 2.6 kg. The total mass is conserved. What is v'₁ if the velocity of the second object is (-2.5 m/s) j + (1.3 m/s) k?
(? i +? j +? k) m/s

(d) Calculate the sum of the kinetic energies in the initial configuration and in the configurations of parts (b) and (c).
Configuration (a)
? J
Configuration (b)
? J
Configuration (c)
? J

To analyze the resulting pattern of bright and dark fringes when laser light passes through a single slit, what fundamental principle of light propagation is used?

A racecar of mass 500 kg is going around a curve of radius 15.0 m, banked at 45∘ . The car has a coefficient of static friction with the track which is 0.200. The car also has a rear wing which produces downforce—“negative lift” due to airflow over the wing, which pushes the car into the track. The downforce is given by ? = ?v² , where ? = 10 kg/m. Find the minimum and maximum speeds between which the car can take the curve without skidding.

MUST ANSWER EVERY PART

In each of the following situations, Emma is in the exact center of a glass-sided fright car speeding to the right at a very high speed v relative to you. For each question, explain your reasoning.

Emma has a flashlight in each hand and directs them at the front and rear ends of the freight car. She then switches the flashlights on at the same time.

In Emma�s frame of reference, which beam of light travels at a greater speed, the one directed toward the front or the one directed toward the rear of the train, or do they travel at the same speed?

In Emma�s frame of reference, which end, front or rear, is struck by light first, or are they struck at the same time? Which end is struck first in your frame of reference?

Calculate the final and initial mechanical energy for trials 1 through 6. Calculate the Diff %.

A block of mass m = 2.90 kg is pushed a distance d = 5.80 m along a frictionless horizontal table by a constant applied force of magnitude F = 16.0 N directed at an angle θ = 21.0° below the horizontal as shown in the figure below. (a) Determine the work done on the block by the applied force. J (b) Determine the work done on the block by the normal force exerted by the table. J (c) Determine the work done on the block by the force of gravity. J (d) Determine the work done by the net force on the block. J

Deserted on a deserted Island you spot a slightly exposed tin can under a tree. Upon opening it you find it’s instructions to a treasure. It reads: “Ten paces from this very tree in a direction twenty degrees south of west lies the first location. Ten paces from this very tree in a direction sixty degrees north of east lie the second location. Walk from this tree exactly the distance and direction you would walk from the first location to the second location and you will find ye treasure. Yar” (a) What are the coordinates of treasure? (b) Use a physical representation in conjunction with the Related Quantities sense-making technique to check the validity of your answer.

1. Consider three point charges at the corners of a triangle as shown in the figure, where q1=6.0x10-9 C , q3= 5.0x10-9 C, q2=-2.0x10-9 C, and the distance of separation are shown in the figure. Calculate the resultant force acting on q3. (Given: 60degree angle at q1 & q2, radius= 5 meters)

please explain. Thank you :)