True-false questions are worth 2 points each, three-choice multiple choice questions are worth 3 points each, five-choice multiple choice questions are worth 6 points each. The maximum possible score is 95. The exam period was 90 minutes; the mean score was 65.8; the median score was 68. Click here to see page1 page2 of the formula sheet that came with the exam.

A 7 kg block is held by three strings as shown in the figure below. The string on the left is pulling horizontally with a force of 233 N. The string in the center pulls down with a force of 50 N, and the string on the right pull at an unknown angle q. (Gravity acts in the vertical direction.)

What is the horizontal component of the tension in the right string?

(a) T_{Rx} = 164 N (b) T_{Rx} = 183 N (c) T_{Rx} = 233 N

(a) T_{Ry} = 50.2 N (b) T_{Ry} = 68.9 N (c) T_{Ry} = 118.6 N (d) T_{Ry} = 159.0 N (e) T_{Ry} = 233.5 N

(a) increase. (b) remain unchanged. (c) decrease.

A person kicks a football (initially on the ground) towards a field goal 35 meters away. As a result of the kick, the ball leaves the ground at an angle of 35 degrees above horizontal with a speed of 20 m/s.

What is the y-component of the acceleration of the ball when it is at the top of its trajectory?

(a) a_{y} = - 9.8 m/s^{2} (b) a_{y} = 0 m/s^{2} (c) a_{y} = + 9.8 m/s^{2}

(a) | v | = 0 (b) | v | = 16.4 m/s (c) | v | = 20 m/s

(a) y_{max} = 6.7 m (b) y_{max} = 8.3 m (c) y_{max} = 9.5 m (d) y_{max} = 11.0 m (e) y_{max} = 20.4 m

(a) d = 15 m (b) d = 21 m (c) d = 38 m (d) d = 43 m (e) d = 47 m

You are on the surface on an unknown planet of radius R = 1.5 × 10^{6} m. You notice that if you throw a ball horizontally at 35 m/s, it goes completely around the planet hitting you in the back 270,000 seconds later with exactly the same speed that you originally threw it.

As the ball traveled around the planet its acceleration was zero.

(T) True (F) False

(a) 1.3 × 10^{19} kg (b) 2.1 × 10^{19} kg (c) 2.8 × 10^{19} kg

A washing machine on the spin cycle spins the tub with an angular velocity of 30 radians/second. A person opens the door, and the tub comes to rest after spinning an additional 270 radians. (Assume constant acceleration.)

What is the magnitude of the angular acceleration of the tub after the door is opened?

(a) 1.67 radians/s^{2} (b) 2.93 radians/s^{2} (c) 9.18 radians/s^{2}

(a) 4 seconds (b) 18 seconds (c) 37 seconds

(a) 100 m/s (b) 115 m/s (c) 120 m/s (d) 155 m/s (e) 185 m/s

Three boxes, A of mass 4 kg, B of mass 2 kg, and C of mass 3 kg, are connected together by mass-less strings, as shown in the figure. They are resting on a horizontal, frictionless surface and the whole assembly is being pulled to the right, as shown in the figure. The tension T_{1} = 36 N.

Calculate the tension T_{2}.

(a) T_{2} = 36 N (b) T_{2} = 20 N (c) T_{2} = 16 N (d) T_{2} = 12 N (e) T_{2} = 8 N

(a) 8 N (b) 14 N (c) 20 N

An arrow is shot vertically upwards.

At the moment it reaches its maximum height, the acceleration of the arrow is(note: positive acceleration is upwards and negative acceleration is downwards towards the Earth)

(a) a < 0 (b) a = 0 (c) a > 0

(a) v < 0 (b) v = 0 (c) v > 0

A bicyclist travels a route through the countryside around Champaign-Urbana. She starts from point A, riding 6 miles due north, then 10 miles east. After stopping for a break of an hour, she resumes her journey by riding 12 miles south, then 2 miles west. This point in her journey is designated B.

At point B in her journey what is the magnitude of her displacement from her starting point A?

(a) 10 miles (b) 20 miles (c) 30 miles

(a) 10.0 mph (b) 5.0 mph (c) 2.5 mph

Box A of mass M_{A}=5 kg is suspended by a massless cord over a massless pulley and connected to a second box B that sits on an incline. The incline is at an angle of 30 degrees with the horizontal, as shown in the figure.

If the boxes are resting in equilibrium, with neither moving up or down, what is the mass of box B, assuming that there is no friction between it and the surface on which it sits?

(a) 5.00 kg (b) 5.77 kg (c) 10.00 kg

Calculate the tension in the string as the block accelerates up the ramp?

(a) T = 20 N (b) T = 24 N (c) T = 49 N

(a) M_{B} = 0.5 kg (b) M_{B} = 1 kg (c) M_{B} = 2 kg (d) M_{B} = 5 kg (e) M_{B} = 10 kg

(a) 1.72 m/s (b) 3.43 m/s (c) 5.21 m/s (d) 7.44 m/s (e) 8.03 m/s

An astronaut is strapped into a rocket that has just been launched vertically upwards. Just after liftoff the acceleration of the rocket is 3g, where g = 9.80 m/s^{2}. If the weight of the person while stationary on the Earth’s surface is 750 N, his apparent weight at this time is

(a) 750 N (b) 1500 N (c) 3000 N

(a) 6,000 km (b) 12,000 km (c) 24,000 km (d) 30,000 km (e) 42,000 km