My Notes

A 5000-kg freight car rolls along rails with negligible friction. The car is brought to rest by a combination of two coiled springs as illustrated in the figure below. Both springs are described by Hooke's law and have spring constants with

k₁ = 1700 N/m

and

k₂ = 3200 N/m.

After the first spring compresses a distance of 33.0 cm, the second spring acts with the first to increase the force as additional compression occurs as shown in the graph. The car comes to rest 49.5 cm after first contacting the two-spring system. Find the car's initial speed.

You are to explain why a baseball can be made to curve in flight according to the appropriate concepts presented in Biomechanics. use terms like magnus force, lift, bernouli principle.

Please select all that are correct.

Select one or more:

a. If two trucks (same model) are driving with the same velocity, the empty truck has less momentum than the truck fully loaded with rubber ducks

b. Law of conservation of momentum only works in 1D and 2D, but no higher

c. A snowball is thrown on a wall. It bounces off, but leaves a white mark behind. This is neither a perfect elastic collision, nor a perfect inelastic collision

d. Halving the time the force is applied on an object doubles the impulse

e. When the law of conservation of momentum is concerned, a pile of sand cannot be used as a closed system because the grains of sand do not stick together and there are too many of them

f. If a cup of hot coffee is defined as a closed system, then the steam coming off the surface has to be accounted for as part of the system

g. Having a pie thrown on one's face is an example of an inelastic collision

h. Velocity, momentum, and impulse can all be expressed in terms of their x-, y-, and z- components

i. When two figure skaters (one going SouthEast, the other going NorthEast) clasp hands, they begin moving West before

A 456 g oscillator has a speed of 98.0 cm/s when its displacement is 3.00 cm and 69.0 cm/s when its displacement is 5.30 cm.

What is the oscillator's maximum speed?

If you increase the potential difference or electromotive force across a resistance in a circuit the current flowing through that device will___.

Question 8 options:

A proton starts on a plate with potential of 5.0 x 10^3 V at y=0m. It then enters a region in which there is magnetic field of 2.0 T pointing out of the page. In a field it travels a semicircular path.

a) what is the radius of the semicircle

b)where (what value of y) doed the proton leave the magnetic field?

c) the proton now passes between a second set of plates with a potential difference of 5 x 10^3 V. What is its velocity after passing through these plates?

d) The proton now enters another region in which there is a magnetic field of 2.0 T pointing out of the page, and it again describes a semicircular path. What is the radius of the semicircle

e) where (what value of y) does the proton emerge from the field now?

In the figure below, the battery has potential difference V = 9.0 V, C2 = 3.0

You are a junior space cadet on an interstellar space station. Your job is to launch a long distance spacecraft. The mass of the spacecraft without any fuel is 1217 kg. This mass is often called dry mass. The rocket engine of the craft can exhaust hot gas at a speed of 2.26 km/s relative to the space craft. How much rocket propellant does the craft need, if you want the craft to reach a final speed of 5.51 km/s relative to the station? In interstellar space the gravitational pull of the stars is negligible.

A 60 kg soccer player jumps vertically upwards and heads the 0.45 kg ball as it is descending vertically with a speed of 27 m/s. If the player was moving upward with a speed of 4.0 m/s just before impact, what will be the speed of the ball immediately after the collision if the ball rebounds vertically upwards and the collision is elastic?
______m/s

If the ball is in contact with the player's head for 20 ms, what is the average acceleration of the ball? (Note that the force of gravity may be ignored during the brief collision time.)
________ m/s²

A 6.10 m length of 2.4 mm -diameter wire carries a 770 mA current when 22.0 mV is applied to its ends. The drift velocity is 2.0×10⁻⁵ m/s .

A. Determine the resistance R of the wire.

Express your answer to three significant figures and include the appropriate units.

B. Determine the resistivity ρ.

Express your answer to two significant figures and include the appropriate units.

C.Determine the current density j.

Express your answer to two significant figures and include the appropriate units.

D. Determine the electric field inside the wire.

Express your answer to two significant figures and include the appropriate units

E. Determine the number n of free electrons per unit volume.

Express your answer using two significant figures.

A particle with a charge of −2.80×10−8 C is moving with an instantaneous velocity of magnitude 42.5 km/s in the xy -plane at an angle of 52.0 o counterclockwise from the +x axis.

Part A What is the direction of the force exerted on this particle by a magnetic field with magnitude 2.00 T in the -x direction?

Part B What is the magnitude of the force exerted on this particle by a magnetic field with magnitude 2.00 T in the -x direction?

Part C What is the direction of the force exerted on this particle by a magnetic field with magnitude 2.00 T in the +z direction? Please, enter your answer as a counterclockwise angle from the +y direction to the direction of the force.

Part D What is the magnitude of the force exerted on this particle by a magnetic field with magnitude 2.00 T in the +z direction?

Divers get “the bends” when bubbles of N2 gas form in their bloodstream if they rise too rapidly from a deep dive. Calculate the solubility (mol L−1) of N2 in water (this is roughly equal to the solubility in blood serum) at sea level and at a depth of 300 ft below the surface of the ocean. It is given that: the density of seawater is 1.01 gcm−3, the density of mercury is 13.6 gcm−3 and the Henry’s constant of N2 is 86 × 103 atm.

Answer is 6.4 × 10−3molL−1 but idk how they got it

Write a creative story to tell about the journey of a jogger from one location in a park to another location. Make up some events and experiences that the jogger goes through on his/her journey. Tell what happens to the jogger throughout the journey (e.g., being chased by a dog or having to slow down for a parade, etc.) As you tell the story, use the terms speed, velocity and acceleration and explain how and why these values change for the jogger as he/she goes through different parts of his/her trip. Your story can be creative and funny or serious as long as you use the terms speed, velocity and acceleration. Make sure that the story conveys the meanings of these terms and the differences between them.

Point B is at < 8.9, 4.0, 14.4 > ft. A force vector of < 15, 37, 21 > pounds is applied at point B.

A) Determine the x-component of the torque of the force about the origin.
(include units with answer)

B) Determine the magnitude of the torque about the origin.
(include units with answer)

C) Point C is at <-3.7, -9.0, 8.1>ft. Determine the x-component of the torque of the force about the point C.
(include units with answer)

D) Determine the magnitude of the torque about the point C.
(include units with answer)