A curve of radius 75 m is banked for a design speed of 100 km/h .

If the coefficient of static friction is 0.36 (wet pavement), at what range of speeds can a car safely make the curve? [Hint: Consider the direction of the friction force when the car goes too slow or too fast.]

A horizontal pipe contains water at a pressure of 140 kPa flowing with a speed of 1.2 m/s . The pipe narrows to one-half its original diameter.

What is the speed of the water?

Express your answer using two significant figures.

What is the pressure of the water?

Express your answer using two significant figures.

A raft is made of 11 logs lashed together. Each is 34.0 cm in diameter and has a length of 5.50 m. How many people (whole number) can the raft hold before they start getting their feet wet, assuming the average person has a mass of 69.0 kg? Do not neglect the weight of the logs. Assume the density of wood is 600 kg/m³

As an aid in working this problem, consult Concept Simulation 26.3. A converging lens has a focal length of 87.00 cm. A 12.0 cm tall object is located 155.0 cm in front of this lens.

(a) What is the image distance? cm

(b) Is the image real or virtual?

real virtual?

(c) What is the image height? Be sure to include proper algebraic sign.
cm?

78.  A commuter train travels between two downtown stations. Because the stations are only 1.00 km apart, the train never reaches its maximum possible cruising speed. During rush hour the engineer minimizes the time interval ?t₁ between two stations by accelerating the rate a₁ = 0.100 m/s² for a time interval ?t₁ and then immediately braking with acceleration a₂ = ?0.500 m/s² for a time interval ?t₂. Find the minimum time interval ?tand the time interval ?t_1.

A beam of photons (q = +1.6 x 10^-19 C) is moving with various speeds in the positive x direction (to the right). It enters a region where there is a uniform magnetic field of magnitude 0.25T pointing in the negative z direction (into the page).

a) The protons feel a force due to this magnetic field. Explain why, and indicate the direction of the force.

b) Not all protons will feel a force of the same magnitude. Why?

c) As a result of the magnetic force, the protons will deviate from their speed original direction towards the right. It is desired that those protons traveling at a speed of 1.75*10^5 m/s don't deviate at all and continue on a straight path to the right. This is to be achieved by turning on an electric field in the same region as the magnetic field. In what direction should the electric field point? Explain.

d) Find the magnitude of the electric field necessary to achieve the result of the previous question.

The ball launcher in a pinball machine has a spring that has a force constant of 1.20 N/cm (Fig. P7.63). The surface on which the ball moves is inclined 10.0

You measure the emission spectrum of hydrogen gas, and see many discrete wavelengths in the emission, of which, one is 102.6nm. To what initial and final states can this wavelength be attributed?. (hint, use a little trial and error to get the intergers)

You see a vehicle move from x= +11.6m to x= +21.8m in a time of 4.76s. If you know that the constant acceleration is 3.65 m/2^2 determine the initial velocity of the vehicle.

Any help is much appreciated. Thanks!

What is an Isotone, isobar and isodiaphers

A red train traveling at 72 km/h and a green train traveling at 144 km/h are headed toward each other along a straight, level track. When they are 840 m apart, each engineer sees the other's train and applies the brakes. The brakes slow each train at the rate of 1.0 m/s2. Is there a collision? If so, give (a) the speed of the red train, (b) the speed of the green train, and (c) the separation between the trains when they collide (0 m). If not, give (a) the speed of the red train (0 m/s), (b) the speed of the green train (0 m/s), and (c) the separation between the trains when they stop.

A charge

q₁ = 2.72

Anna, Anh and Amir are each given a sample of an unknown polymer and asked to calculate the density of their sample by measuring the mass and volume to determine if it could be polyaniline. They find a published value for the density of polyaniline to be 1.33 g cm^-3.

Amir quotes his final experimental value of the density of his sample with its uncertainty to be 1.36 ± 0.01 g cm^-3.

Select as many of the following statements that would be supported by Amir’s result.

A stationary nucleus of charge Q, radius R of mass M is divided into two daughter nuclei of
the same size and charge, which repel each other to innite distance apart after the fission.
Assume the charge density p remains the same before and after the nuclear fission. (i)How
much kinetic energy is generated.(ii)What will be the mass of daughter nuclei ?
(b)How much energy would be generated from the nuclear fission of one mole of a nuclei with
Z = 92, R = 1:0fm(Assume the nuclear fission takes place as described in part (a)).

A roller coaster is created with a hill of height 125 m and a loop with radius 45m. To make the crowds swoon, a new cart is brought in: a hollow sphere of mass 250kg and radius 2m, capable of carrying four passenger of total mass, 400kg.

The hollow sphere is capable of carrying passengers around the roller coaster separately. Friction although present is mostly negligible.

1.1 What is the initial energy of the system if the cart is released from rest?

1.2 What is the speed of cart when it reaches the bottom of the hill?

1.3 What is its speed at the top of the roller coaster loop?

1.4 What is the minimum speed to get around the loop? (Does it change or is it still the same?)

1.5 If the hollow sphere is replaced by a hollow disk with same mass and radius as the sphere, does the

speed in 1.4 change?