1) A car is clocked at 25 m/s in a 50-mi/h zone. Is it speeding?

2) Use the definition of the meter to determine how far light travels in exactly 1 ns. Express your answer in meters to three significant figures.

3) Express a 85 mi/h speed limit in meters per second. Express your answer in meters per second.

4) GPS satellites complete approximately two full orbits each day. Express that rate in degrees per hour. Express your answer in degrees per hour.

5) One m/s is how many km/h? Express your answer in kilometers per hour to three significant figures.

6) Add 3.13105 m and 2.23103 km . Express your answer with the appropriate units.

Suppose a radioactive nucleus has a half-life of 2 min. and suppose the counting rate at time t = 0 is 3000 counts/10 sec. a. What is the counting rate after 2 min? b. After 6 min? c. After 10 min? d. After 20 min?

i)Why is a converging field necessary in a magnetic separator? ii) Briefly describe the working principle of a low-intensity magnetic separator. iii) Explain the working principle of an induced roll magnetic separator.Why is a converging field necessary in a magnetic separator? ii) Briefly describe the working principle of a low-intensity magnetic separator. iii) Explain the working principle of an induced roll magnetic separator.

The activity of a sample of a radioisotope at some time is 10.1 mCi and 0.36 h later it is 6.60 mCi. Determine the following:

(a)Decay constant (in s⁻¹)

(b) Half-life (in h)

(c) Nuclei in the sample when the activity was 10.1 mCi

(d) Activity (in mCi) of the sample 1.90 h after the time when it was 10.1 mCi

We aim a red (620 nm) laser onto a small screen that has two slits that are 0.1 mm apart. Each slit has a width of 0.03 mm.The light coming out of the two slits is projected onto a big screen a distance X from the slits. In the photo on the right you can see the pattern that’s visible on the big screen.Using a ruler, we determine that the distance between two adjacent bright spots is equal to 12 mm.The red laser has a wavelength of 620 nm and its beam has a circular cross section with a diameter of 0.8 mm. The power rating of the laser “1.5 mW“ (i.e. 1.5 milliwatts) which we may assume is the power of the light coming out of the laser.

1. [4 points] Calculate how many photons are being emitted by the laser each second.

Which ONE of the following statements regarding Projectile Motion is FALSE?

1)A block of mass m1 = 8.00 kg and a block of mass m2 = 12.0 kg are connected by a massless string over a pulley in the shape of a solid disk having radius R = 0.350 m and mass M = 12.0 kg. The coefficient of kinetic friction between block m1 and the table is 0.27. a) Draw force diagrams of both blocks and of the pulley. b) Determine the acceleration of the two blocks. c) Determine the tensions ?1 and ?2 in the string on both sides of the pulley. d) How would the answer for ?1 and ?2 change is the pulley were massless?

2)During a certain time interval the angular position of a swinging door is described by θ = 5.3 + 7.1t + 4.5t 2 , where θ is in radians and t is in seconds. Determine (a) the angular position at t = 2 sec, (b) angular speed at t = 2 sec, and (c) angular acceleration of the door at t = 2 sec.

3)A figure skater is spinning with an angular velocity of 16 rad/s. She then comes to a stop over a brief period of time. During this time, her angular displacement is 5 rev. Determine (a) her average angular acceleration and (b) the time during which she comes to rest

4)A disk 6.00 cm in radius rotates at a constant rate of 98.0 rev/s about its central axis. (a) Determine the tangential speed at a point 4.00 cm from its center. (b) Determine the centripetal acceleration of a point on the rim.

5)Two girls ?1 = 21.0 kg and ?2 = 29.0 kg are standing 1.00 m away from the center of a rotation platform (Figure (a)), and the platform rotates at angular speed of 3.00 rad/s. Then both girls begin to walk towards the edge of the platform. If the radius of the platform is 2.00 m, what is the final angular speed of the system, when the girls reach the platform’s edge (Figure (b))? Model the platform as a uniform disk of mass M =350 kg, and the girls as point masses. The moment of inertia of a disk of mass M and radius R is 2 2 1 I disk = MR .

Explain the following i)Refraction ii) Wave mode iii)Bloch body

In radio communications, multiple-input, multiple-output (MIMO) is a method for multiplying the capacity of a radio link using multiple transmissions and receiving antennas to exploit multipath propagation. Explain with a proper diagram how MIMO achieves better efficiency and utilization of channels.

A firefighter carries a hose up a ladder to a height of 10.0 m, so that she can spray water onto a burning roof that is 9.00 m high. She holds the hose horizontally, and sees that the water strikes the roof 7.0 m in front of her position (i.e. horizontal component of displacement is 7.0 m). The hose is connected to a very large, pressurized chamber in the fire truck, which is sitting at ground level. What is the pressure in the large reservoir? (Ignore air resistance; don’t be off by 1 atm.)

*include sketch/diagram

A cannon is rolling to the right at a speed of 0.50 c. In its own frame, it fires a 8.5 kg cannonball to the right at a speed of 0.72 c . Let A be the value of the cannonball’s momentum in the frame of the ground according to classical physics; let B be the same momentum according to special relativity. Which of the following is correct?

NO PICTURE ANSWERS:

Explain the model for Jovian planet formation.

How do you calculate the radioactive isotope inventory of all present elements when a sample 1g of 5% U-235 and 95% U-238 is left to decay for a year?

1. Do I understand AC-circuit enough to be able to obtain v(t) and i(t) in a given AC-circuit with various combinations of R, L and C?

   1a. Can I tell or plot which leads/lags which?

   1b. time-dependent values of voltage, current, power, etc.

   1c. maximum values of voltage, current, power, etc.,

   1d. rms values of voltage, current, etc.

   1e. time-average of power dissipated by a resistor

   1f. Do I know how to plot graphs of these values?

   1g. Do I know the definitions of these values and/or the relationships between these values?

2. Do I understand AC-driven RLC-circuit enough to be able to obtain?

   2a. reactance, impedance, resonance, etc.?

   2b. Do I know how to plot graphs of these values?

   2c. Do I know the definitions of these values and/or the relationships between these values?