Physics Exam One

The speed of a wave pulse on a string depends on the tension,F, in the string and the mass per unit length, u, of the string. Tension has SI units of kg ∙ m ∙ s-2 and the mass per unit length has SI units of kg ∙ m-1. What combination of F and u must the speed of the wave be proportional to? A) sq u /F B) sq uF C) sq F /u D) u/ F E) F /u

sq F/u

Two particles, A and B, are in uniform circular motion about a common center. The acceleration of particle A is 4.7 times that of particle B. Particle B takes 2.4 times as long for a rotation as particle A. The ratio of the radius of the motion of particle A to that of particle B is closest to: A) 3.8 B) 11 C) 2.0 D) 0.51 E) 0.82

.82

Two identical objects A and B fall from rest from different heights to the ground. If object B takes twice as long as A to reach the ground, what is the ratio of the heights from which A and B fell? Neglect air resistance. A) 1 : 8 B) 1 : 4 C) 1 : 2 D) 1 : sq 2

1 : 4

A hockey puck slides off the edge of a table with an initial velocity of 28.0 m/s. and experiences no air resistance. The height of the tabletop above the ground is 2.00 m. What is the angle below the horizontal of the velocity of the puck just before it hits the ground? A) 31.8° B) 12.8 ° C) 77.2° D) 72.6 ° E) 12.6 °

12.6

The components of vectors A and B are given as follows: Ax = +7.6 Bx = -5.1 Ay = -9.2 By = -6.8 The magnitude of the vector difference B - A , is closest to: A) 16 B) 13 C) 3.4 D) 170 E) 3.5

13

A car accelerates from 5.0 m/s to 21 m/s at a rate of 3.0 m/s2. How far does it travel while accelerating? A) 69 m B) 41 m C) 207 m D) 117 m

69

You walk 35 m to the north, then turn 60° to your right and walk another 45 m. How far are you from where you originally started? A) 40 m B) 69 m C) 76 m D) 36 m

69

A ball is thrown straight upward with a velocity of 18 m/s. How much time passes before the ball strikes the ground? Disregard air resistance. A) 1.8 s B) 3.7 s C) 1.1 s D) 0.6 s

3.7

A projectile is fired at time t = 0.0s, from point 0 at the edge of a cliff, with initial velocity components of νox= 80 m/s and νoy = 200 m/s. The projectile rises, then falls into the sea at point P. The time of flight of the projectile is 50.0 s. Figure 3.2b In Figure 3.2b, the x-coordinate of the projectile when its y-component of velocity equals 160 m/s upward is closest to: A) 330 m B) 310 m C) 280 m D) 290 m E) 340 m

330

Assuming equal rates of acceleration in both cases, how much further would you travel if braking from 56 mi/h to rest than from 28 mi/h. A) 3.2 times farther B) 5.2 times farther C) 4.8 times farther D) 4 times farther

4 times farther

A projectile is fired from the origin (at y = 0 m) as shown in Figure 3.1. The initial velocity components are V0x = 940 m/s and V0y = 96 m/s. The projectile reaches maximum height at point P, then it falls and strikes the ground at point Q. In Figure 3.1, the y-coordinate of point P is closest to: A) 45,080 m B) 45,550 m C) 470 m D) 90,160 m E) 940 m

470

A test rocket is fired straight up from rest with a net acceleration of 20 m/s2. After 4 seconds the motor turns off, but the rocket continues to coast upward. What maximum elevation does the rocket reach? A) 160 m B) 487 m C) 320 m D) 327 m E) 408 m

487

What is the maximum distance we can shoot a dart, provided our toy dart gun gives a maximum initial velocity of 7.76 m/s? A) 3.88 m B) 6.14 m C) More information needed. D) 12.28 m

6.14

A motorist makes a trip of 180 miles. For the first 90 miles she drives at a constant speed of 30 mph. At what constant speed must she drive the remaining distance if her average speed for the total trip is to be 40 mph? A) 55 mph B) 52.5 mph C) 60 mph D) 45 mph E) 50 mph

60