An infant’s pulse rate is measured to be 130 ± 5 beats/min. What is the percent uncertainty in this measurement?
26.0%
3.85%
5.00%
2.50%
A person measures his or her heart rate by counting the number of beats in 30 s. If 40 ± 1 beats are counted in 30.0 ± 0.5 s, what is the heart rate and its uncertainty in beats per minute?
80 ± 3 beats/min
80 ± 5 beats/min
80 ± 1 beats/min
80 ± 2 beats/min
On December 10, 1954, John Paul Stapp rode a rocket sled, accelerating from rest to a top speed of 282 m/s (1015 km/h) in 5.00 s, and was brought back to rest in 1.40 s. Calculate his acceleration and deceleration.
56.4 m/s^2, -201 m/s^2
56.4 m/s^2, -56.4 m/s^2
56.4 m/s^2, -44.1 m/s^2
201 m/s^2, -56.4 m/s^2
You throw a ball straight up with an initial velocity of 15.0m/s. It passes a tree branch on the way up at a height of 7.00 m. How much additional time will pass before the ball passes the tree branch on the way back down
9.38 s
9.80 s
1.92 s
15 s
An unwary football player collides with a padded goal post while running at a velocity of 7.50 m/s and comes to a full stop after compressing the padding and his body 0.350 m. What is his deceleration?
-0.0124 m/s^2
-160 m/s^2
-55.6 m/s^2
-80.4 m/s^2
A new landowner has a triangular piece of flat land she wishes to fence. Starting at the west corner, she measures the first side to be 80.0 m long and the next to be 105 m. These sides are represented as displacement vectors A from B. She then correctly calculates the length and orientation of the third side C. What is her result?
74.3 m, 36.2 degrees
54.7 m, 36.2 degrees
92.2 m, 53.6 degrees
50.3 m, 53.6 degrees
A daredevil is attempting to jump his motorcycle over a line of buses parked end to end by driving up a 32 degree ramp at a speed of 40.0 m/s (144 km/h). How many buses can he clear if the top of the takeoff ramp is at the same height as the bus tops and the buses are 20.0 m long?
4.3 buses
7.5 buses
34 buses
150 buses
An ice hockey player is moving at 8.00 m/s when he hits the puck toward the goal. The speed of the puck relative to the player is 29.0 m/s. The line between the center of the goal and the player makes a 90.0 degree angle relative to his path. What angle must the puck’s velocity make relative to the player (in his frame of reference) to hit the center of the goal?
74 degrees
9.27 degrees
45 degrees
16 degrees
Two children pull a third child on a snow saucer sled exerting forces F1and F2. Find the acceleration of the 49.00-kg sled and child system.
0.44 m/s^2
0.15 m/s^2
0.14 m/s^2
14.3 m/s^2
Calculate the tension in a horizontal strand of spider web if the same spider sits motionless in the middle of it much like the tightrope walker in Figure 4.17. The strand sags at an angle of 12 degrees below the horizontal. The mass of the spider is 8.00 x 10^-5 kg.
1.88 x 10^-3 N
9.40 x 10^-4 N
1.92 x 10^-4 N
4.00 x 10^-4 N
A 1100-kg car pulls a boat on a trailer. What total force resists the motion of the car, boat, and trailer, if the car exerts a 1900-N force on the road and produces an acceleration of 0.550 m/s^2? The mass of the boat plus trailer is 700 kg.
910 N
1.72 N
3.14 N
182 N
Consider the 52.0-kg mountain climber. Find the tension in the rope. Assume that the force is exerted parallel to her legs. Assume negligible force exerted by her arms.
273 N
512 N
209 N
760 N
Find the terminal velocity of a spherical bacterium (diameter 2.00 μm) falling in water. You will first need to note that the drag force is equal to the weight at terminal velocity. Take the density of the bacterium to be 1.10 × 10^3 kg/m^3. The viscosity of water is 1.00 x 10^-3 kg/m.
1.20 x 10^-6 m/s
4.20 x 10^-6 m/s
2.40 x 10^-6 m/s
4.52 x 10^-14 m/s
A vertebra is subjected to a shearing force of 500 N. Find the shear deformation, taking the vertebra to be a cylinder 3.00 cm high and 4.00 cm in diameter. The shear modulus for tension in the bone is 80 x 10^9 N/m^2.
1.49 x 10^-7 m
3.73 x 10^-8 m
6.72 x 10^6 m
1.49 x 10^-11 m
What is the radius of a bobsled turn banked at 75.0 degrees and taken at 30.0 m/s, assuming it is ideally banked?
0.820 m
24.6 m
355 m
95.0 m
Three lead spheres, of mass 10 kg each, are located at three corners of a square of side length 45 cm. A bead is released at the forth corner. By considering the gravitational forces among the four objects only, determine the magnitude and direction of the acceleration of the bead when released.
1.65 x 10^-9 m/s^2
4.67 x 10^-9 m/s^2
3.30 x 10^-9 m/s^2
6.32 x 10^-9 m/s^2
Earth is a spherical body, of radius 6,376 km, which completes a full rotation about its axis in 24 h. How long (in hours) should the day on Earth be so that a person at the equator is able to float freely above the ground?
1.77 hr
48 hr
1.41 hr
127 hr
A 60.0-kg skier with an initial speed of 12.0 m/s coasts up a 2.50-m-high rise. Find her final speed at the top, given that the coefficient of friction between her skis and the snow is 0.0800.
9.46 m/s
11.8 m/s
6.25 m/s
3.15 m/s
A 100-g toy car is propelled by a compressed spring that starts it moving. What is its final speed if its initial speed is 2.00 m/s and it coasts up the frictionless slope, gaining 0.180 m in altitude.
0.687 m/s
2.00 m/s
0.180 m/s
4.89 m/s
A 70.0-kg ice hockey goalie, originally at rest, catches a 0.150-kg hockey puck slapped at him at a velocity of 35.0 m/s. Suppose the goalie and the ice puck have an elastic collision and the puck is reflected back in the direction from which it came. What would the final velocity of the player?
0.150 m/s
-34.9 m/s
-35.2 m/s
34.9 m/s
A 5.50-kg bowling ball moving at 9.00 m/s collides with a 0.850-kg bowling pin, which is scattered at an angle of 85.0 degrees to the initial direction of the bowling ball and with a speed of 15.0 m/s. Calculate the final velocity (magnitude and direction) of the bowling ball.
9.10 m/s, 14.7 degrees
3.00 m/s, 5 degrees
15.0 m/s, 55 degrees
5.90 m/s, 16 degrees
Suppose the weight of the drawbridge is supported entirely by its hinges and the opposite shore, so that its cables are slack. What fraction of the weight is supported by the opposite shore if the point of support is directly beneath the cable attachments? The mass of the bridge is 2500 kg.
1/5
1/3
1/4
1/6
Unlike most of the other muscles in our bodies, the masseter muscle in the jaw is attached relatively far from the joint, enabling large forces to be exerted by the back teeth. (a) Using the information in the figure, calculate the force exerted by the lower teeth on the bullet.
60 N
84 N
116 N
12 N
A thin uniform rod (of mass 10 kg and length of 1.2 m) is attached to a friction-free pivot. Initially, the rod is balanced vertically above the pivot (position A). If the rod falls from rest, calculate the angular acceleration at position B.
12.3 rad/s^2
2.72 rad/s^2
24.5 rad/s^2
5.44 rad/s^2
The triceps muscle in the back of the upper arm extends the forearm. This muscle in a professional boxer exerts a force of 2.00 × 10^3 N with an effective perpendicular lever arm of 3.00 cm, producing an angular acceleration of the forearm of 120 rad/s^2. What is the moment of inertia of the boxer’s forearm?
0.25 kg x m^2
0.75 kg x m^2
0.5 kg x m^2
1.5 kg x m^2