1. Explain why you can maintain contraction of the hamstring muscles over time.

2. Explain why you can sustain the same contraction with a 5-lb weight attached to the ankle.

3. Explain why the hamstring muscles fatigue faster with the 5-lb ankle weight.

4. State the order of recruitment of muscle fiber types.

Find the distribution of temperature inside a sphere of radius a when the surface of the upper half is held at 100°C and the surface of the lower half at 0°C

Describe the difference between an insulator and a conductor. What are some examples of each? Name some examples when you would want to use each of them.

John was swimming in the river. His swimming velocity was 1.2 m/s due east. The water was running at 0.4 m/s due west. John’s projected area in the water was 0.45 m2. Water density was 1000 kg/m3. The coefficient of drag was 0.2. (a) What was John’s velocity relative to the water? (b) What was the pressure drag force from the water? After a little while, John turned around and now is swimming at 1.2 m/s due west. (c) What is John’s velocity relative to the water now? (d) What is the pressure drag force from the water now? (e) What is the percentage of change in pressure drag force?

An object is placed 12 cm in front of a diverging lens with a focal length of 7.9 cm.

(a) Find the image distance and determine whether the image is real or virtual.

(b) Find the magnification

A 110-kg rugby player is sliding on a muddy field at a speed of 2 m/s toward the right as a 82-kg player is slipping at a speed of 3 m/s toward the left. As the two players collide, they grab onto each other and slide away together as one.

What kind of collision was this?

Set up the conservation of linear momentum for this collision, and determine the shared velocity (magnitude & direction) of the players immediately after the collision.

Would the players' total kinetic energy before the collision be equal to their total kinetic energy after? yes/no

a) Explain the production of x-rays

b) What is the typical energy range for Compton scattering and why?

c) Why does pair production require a minimal energy and what is it?

What is the energy released in this alpha decay reaction 23090Th?22688Ra+42He90230Th?88226Ra+24He? (The atomic mass of 230Th230Th is 230.033139 u and that of 226Ra226Ra is 226.025402 u)

1. A stonemason is dragging a 60-kg marble block 4 m across a floor by pulling on a rope attached to the block. He pulls with a horizontal force of 210 N. The coefficient of kinetic friction between the block and the floor is 0.30.  The next five questions have to do with this scenario.  Draw yourself a free-body diagram on the block.

   How much work was done by the stonemason in dragging this block?

   	a.	100 J
   	b.	560 J
   	c.	840 J
   	d.	1230 J

2. Add up the y-components, ΣF_y, and determine the normal force the floor exerts upward on the block.

   	a.	588 N
   	b.	345 N
   	c.	279 N
   	d.	126 N

3. Using your result from above, calculate the kinetic frictional force between the block and the floor.

   	a.	45.6 N
   	b.	56.7 N
   	c.	98.5 N
   	d.	176.4 N

Determine the work done by friction.

1. 	a.	345.2 J
   	b.	-705.6 J
   	c.	-980.1 J
   	d.	1257.9 J

2. Add up the x-components, ΣF_x , and determine the block's acceleration.

   	a.	3.7 m/s2
   	b.	0.91 m/s2
   	c.	0.56 m/s2
   	d.	0.38 m/s2

After a heavy snowfall, Annie wants to drag a sled loaded with toys across her level backyard floor, by pulling a rope at an angle of 26 degrees up from the snowy floor. When Annie increases her pull to 25N, the sled starts. Two days later, all the snow has melted leaving the concrete exposed. Annie pulls on the loaded sled, but now it has become harder to get it to start. Annie does not want to change the pulling angle, because it is most natural for her. Answer the 3 parts:

a) Draw a free body diagram for Annie's sled, labeling forces

b) The coefficients of static friction for snow and concrete are 0.15 and 0.95, respectively. How large is the normal force of the floor in the two cases (snow and concrete)?

c) How much mass does Annie need to remove from the sled, to be able to start the sled on the concrete by pulling just as hard as she did earlier on the snow?

Estimate the number of Solar neutrinos passing through a detector on the Earth in one second. Assume that the detector has a surface area of 1.0 square meters and is aligned so that it faces directly towards the centre of the Sun. Assume that every neutrino travels without any change (i.e. none are absorbed or converted to a different particle). Also assume that the energy carried out of the Sun by the neutrinos is negligible

A ) A 2-?C point charge is embedded in the center of a solid Pyrex sphere of radius R = 15 cm.

(1) Calculate the electric field strength E just beneath the surface of the sphere. (in N/C ) - Answer them in term of "e" like [ ex. : 1.43e+05? ]

(2) Assuming that there are no free charges, calculate the strength of the electric field just outside the surface of the sphere. ( in N/C ) Answer them in term of "e" like [ ex. : 1.43e+05? ]?

(3) What is the induced surface charge density ?ind on the surface of the Pryex? (in C/m^2) Answer them in term of "e" like [ ex. : 1.43e+05? ]?

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B) Trying with diffrent variables, a 1-?C point charge is embedded in the center of a solid Pyrex sphere of radius R = 12 cm.

(1) Calculate the electric field strength E just beneath the surface of the sphere.( in N/C )? Answer them in term of "e" like [ ex. : 1.43e+05? ]?

(2) Assuming that there are no free charges, calculate the strength of the electric field just outside the surface of the sphere.( in N/C )? Answer them in term of "e" like [ ex. : 1.43e+05? ]?

(3) What is the induced surface charge density ?ind on the surface of the Pryex?(in C/m^2) Answer them in term of "e" like [ ex. : 1.43e+05? ]

A) Plot the first five particle in a box wavefunctions for an electron in a 10 Å box

(starting at n = 1). Choose two of these and plot their probability density. Offer a brief

interpretation.

B) (10) Calculate the probability you would find the electron in the right-hand . of the

box (right-hand meaning larger values of the spatial variable) if the electron were

described by your fifth wavefunction (highest energy where n = 5). Calculate the

probability you would find the electron in the left-hand 1/4 of the box

C) (15) Suppose your electron were described as an equal superposition of the first and

second wavefunctions. Normalize this new function and then calculate the probability

you would find the electron in the right-hand 1/4 of the box. Calculate the probability

you would find the electron in the left-hand 1/4 of the box.