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 96. The exam period was 90 minutes; the mean score was 82.7; the median score was 87. Click here to see page1 page2 of the formula sheet that came with the exam.

An 11 kg box is pushed on a horizontal floor at constant velocity. There is friction between the box and the floor. As shown in the figure, the force F = 25 N makes an angle θ = 20° with the horizontal.

What is the friction coefficient, μ, between the box and the floor?

(a) μ = 0.00 (b) μ = 0.10 (c) μ = 0.20 (d) μ = 0.30 (e) μ = 0.40

(a) decrease. (b) stay the same. (c) increase.

(a) m = 17 kg (b) m = 25 kg (c) m = 32 kg

A car starts from rest and moves with constant acceleration along a straight line. After traveling 150 m, it has a speed of 30 m/s.

What is the acceleration of the car?

(a) 0 m/s^{2} (b) 1 m/s^{2} (c) 2 m/s^{2} (d) 3 m/s^{2} (e) 4 m/s^{2}

(a) 10 s (b) 20 s (c) 30 s (d) 40 s (e) 50 s

(a) 210 m (b) 300 m (c) 600 m

A centrifuge spins a 0.28 kg sample that is 0.15 m from its axis at a speed of 78.5 radians per second.

What is the speed of the sample in the centrifuge?

(a) |v| = 6.8 m/s (b) |v| = 9.3 m/s (c) |v| = 11.8 m/s

(a) |F| = 0 (b) |F| = 168 N (c) |F| = 260 N (d) |F| = 283 N (e) |F| = 329 N

What is the angular acceleration of the centrifuge as it slows down?

(a) |α| = 9.8 rad/s^{2} (b) |α| = 12.2 rad/s^{2} (c) |α| = 15.7 rad/s^{2}

(a) 25 (b) 50 (c) 100

(a) F_{N} < Mg (b) F_{N} = Mg (c) F_{N} > Mg

A 25 kg weight is suspended by two strings, as shown in the figure below. The left string makes an angle of 35 degrees with respect to the horizontal, and the right string makes an angle of 25 degrees with respect to the horizontal. The vertical component of the tension of the left hand string is T_{Ly} = 147 newtons.

What is the vertical component of the tension in the string on the right?

(a) T_{Ry} =73.8 N (b) T_{Ry} =98.0 N (c) T_{Ry} =122.5 N

(a) T_{Lx} = 150 N (b) T_{Lx} = 210 N (c) T_{Lx} = 281 N

(a) 67 N (b) 105 N (c) 194 N (d) 225 N (e) 303 N

A student who can swim with a speed of 2.6 m/s in still water wants to get to the other side of a 350 m wide river whose waters flows downstream at 1.1 m/s. If she swims across, starting at point A, in such a way that the time taken is the smallest possible,

How many seconds will it take her to cross the river?

(a) 350/1.1 (b) 350/2.6 (c) 350/3.7

(a) 148 m (b) 202 m (c) 259 m

A massless rope connects block A to block B across a frictionless pulley as shown in the figure. Block B hangs vertically downwards and block A slides across a horizontal surface with a coefficient of kinetic friction, μ_{k}. Block A has a mass of 10 kg and block B has a mass of 6 kg. The tension, T, in the string is 48 N.

What is the acceleration of the blocks?

(a) 6.1 m/s^{2} (b) 3.7 m/s^{2} (c) 1.8 m/s^{2}

(a) 0.3 (b) 0.2 (c) 0.1

A stone is thrown vertically upward at 15 m/s. Neglect friction due to the air.

What is the stone’s velocity after 2 seconds?

(a) 4.6 m/s upward (b) 2.2 m/s upward (c) 0 m/s (d) 2.2 m/s downward (e) 4.6 m/s downward

(a) t = 2.1 s (b) t = 3.1 s (c) t = 4.1 s (d) t = 5.1 s (e) t = 6.1 s

(a) upwards. (b) zero. (c) downwards.

The quarterback of the football team throws the ball at a speed of 20 m/s at an angle of 25 degrees above horizontal as shown below. The ball is caught by the receiver at the same height above the ground from which it was thrown by the quarterback.

What is the speed |v| of the ball when it reaches its maximum height?

(a) |v| = 0 (b) |v| = 8.5 m/s (c) |v| = 18 m/s

(a) h = 3.6 m (b) h = 7.8 m (c) h = 20 m

(a) S = 27 m (b) S = 31 m (c) S = 34 m

(a) |v| = 8.5 m/s (b) |v| = 18 m/s (c) |v| = 20 m/s