A woman stands on a scale in a moving elevator. Her mass is 61.0 kg, and the combined mass of the elevator and scale is an additional 725 kg. Starting from rest, the elevator accelerates upward. During the acceleration, the hoisting cable applies a force of 9340 N. What does the scale read (in N) during the acceleration?

1- Block 1 (mass 2.0 kg) is moving to right at speed of 5.0 m/s. It collides with block 2 (mass 3.0 kg) that is moving to the right at speed of 3.0 m/s.

a) What is the speed of the blocks if the collision is completely inelastic? How much kinetic energy is lost? (3.8 m/s, 2.4 J)

b) What is the final speed of the blocks if the collision is elastic? (v1 = 2.6 m/s, v2 = 4.6 m/s)

2 - A solid uniform sphere of mass 5.0 kg and diameter 40 cm, rolls down a hill without slipping. If the velocity of the sphere downhill is 2.0 m/s.

a) what is the height of the hill? (29 cm)

b) What is the angular momentum of the sphere downhill? (0.8 kg*m/s)

I know the answers I just need to know how to get to those answers!

A passenger with mass 85 kg rides in a Ferris wheel. The seats travel in a circle of radius 35 m. The Ferris wheel rotates at constant speed and makes one complete revolution every 25 s.

A)

Calculate the magnitude of the net force exerted on the passenger by the seat when she is one-quarter revolution past her highest point.

B)

Calculate the direction of the net force exerted on the passenger by the seat when she is one-quarter revolution past her highest point.

I need exact answers. Thank you

A football receiver running straight downfield at 5.20 m/s is 10.5 m in front of the quarterback when a pass is thrown downfield at 23.0° above the horizon (see the figure below).

If the receiver never changes speed and the ball is caught at the same height from which it was thrown, find the football's initial speed, the amount of time the football spends in the air, and the distance between the quarterback and the receiver when the catch is made.

(a) the football's initial speed (in m/s)

___________ m/s

(b) the amount of time the football spends in the air (in s)

________________ s

(c) the distance between the quarterback and the receiver when the catch is made (in m)

_____________m

A beam of electrons is shot into a uniform downward electric field of magnitude 1.11x10^3 N/C. The electrons have an initial velocity of 1.02x10^7 m/s, directed horizontally. The field acts over a small region, 5.00 cm in the horizontal direction.

(a)Find the magnitude and direction of the electric force exerted on each electron.
-magnitude:
-direction:

(b) How does the gravitational force on an electron compare with the electric force?

   -The gravitational force is much smaller than the electric force. OR -The gravitational force is much larger than the electric force.

(c) How far has each electron moved in the vertical direction by the time it has emerged from the field?

(d) What is the electron's vertical component of velocity as it emerges from the field? (Up is the positive y-direction.)

(e) The electrons move an additional 19.8 cm after leaving the field. Find the total vertical distance that they have been deflected by the field.

A 0.600 kg block is attached to a spring with spring constant 18.0 N/m . While the block is sitting at rest, a student hits it with a hammer and almost instantaneously gives it a speed of 40.0 cm/s . What is the block's speed at the point where x= 0.550 A?

Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye. The brief pulses of energy absorbed by the retina welds the detached portion back into place. In one such procedure, a laser beam has a wavelength of 810 nmand delivers 250 mW of power spread over a circular spot 510 μm in diameter. The vitreous humor (the transparent fluid that fills most of the eye) has an index of refraction of 1.34.

Part A

If the laser pulses are each 1.50 ms long, how much energy is delivered to the retina with each pulse?

Express your answer with the appropriate units.

Part B

What average pressure would the pulse of the laser beam exert at normal incidence on a surface in air if the beam is fully absorbed?

Express your answer with the appropriate units.

Part C

What are the wavelength of the laser light inside the vitreous humor of the eye?

Express your answer with the appropriate units.

Part D

What is the frequency of the laser light inside the vitreous humor of the eye?

Express your answer with the appropriate units.

Part E

What is the maximum value of the electric field in the laser beam?

Express your answer with the appropriate units.

Part F

What is the maximum value of the magnetic field in the laser beam?

A spy satellite is in circular orbit around Earth. It makes one revolution in 5.99 hours. How high above Earth's surface is the satellite?

: 10368477 m
11.[2pt]
What is the satellite's acceleration?

A point charge q1 = -4.00 nC is at the point x = 0.60 m, y = 0.80 m , and a second point charge q2 = +6.00 nC is at the point x = 0.60 m , y = 0.

A) Calculate the magnitude of the net electric field at the origin due to these two point charges

B) Calculate the direction of the net electric field at the origin due to these two point charges.

A small spring-loaded launcher is designed to fire steel ball bearings with masses of 0.24 kg . When setting the launcher, you compress the spring a distance of 12 cm . You then fire the launcher straight up and find that the projectiles reach a maximum height of 1.2 m above the point that they leave the launcher. You load another ball bearing, compress the spring a distance of 19 cm , and place it horizontally at the edge of a table that is 0.6 m tall. You fire the ball from the edge of the table. How far from the base of the table does it hit the ground?

The "reaction time" of the average automobile driver is about 0.7 s . (The reaction time is the interval between the perception of a signal to stop and the application of the brakes.) An automobile can slow down with an acceleration of 12.4 ft/s2 .

Part A

Compute the total distance covered in coming to a stop after a signal is observed from an initial velocity of 15.4 mi/h . (in a school zone)

Part B

Compute the total distance covered in coming to a stop after a signal is observed from an initial velocity of 56.0 mi/h .

A 0.420 kg iron horseshoe that is initially at 450°C is dropped into a bucket containing 19.7 kg of water at 22.6°C. What is the final equilibrium temperature (in °C)? Neglect any heat transfer to or from the surroundings. Do not enter units.

On the planet Newtonia, a simple pendulum having a bob with a mass of 1.35kg and a length of 187.0cm takes 1.42s , when released from rest, to swing through an angle of 12.0?, where it again has zero speed. The circumference of Newtonia is measured to be 5.15

A place-kicker must kick a football from a point 36.0 m (about 40 yards) from the goal. Half the crowd hopes the ball will clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 20.2 m/s at an angle of 51.0° to the horizontal.

(a) By how much does the ball clear or fall short (vertically) of clearing the crossbar? (Enter a negative answer if it falls short.)

Find the two initial velocity components, and from them and the equations of motion, determine the time and height when the football has traveled the required distance measured along the ground. m

(b) Does the ball approach the crossbar (and cross above or beneath it) while still rising or while falling?

rising

or falling