Physics 201- Exam 1,2,3 questions

A research submarine has a 20.0-cm radius window that is rated to withstand forces up to 1.10 x 10^6 N. Find the maximum pressure that can be acting on the surface of the window before it fails

8.75 x 10^6 Pa

A water balloon is launched horizontally from a 15.0 m-high dorm window. The balloon is launched at a speed of 12.0 m/s a.) How long is the balloon in the air? b.) How far from the base of the building does the balloon land?

a.) 1.22 seconds b.) 21.93 m

Air at 20.0 C (pair=1.20 kg/m^3) flows through a horizontal pipe with a radius of 0.200 cm. The pipe extends to a wider radius of 1.00 cm, at which point the air is traveling at a speed of 6.00 m/s a.) From continuity, determine the speed of the air in the narrow section of the pipe b.) Assuming the pipe is horizontal, use Bernoulli's equation to find the pressure difference P2-P1 between the two sections

a.) 1.50 m/s b.) 1.35 x 10^4 Pa

A wheel accelerates with a constant rotational acceleration of 4.5 rad/s^2 from an initial rotational speed of 1.0 rad/s. a.) through what angle does the wheel turn in the first 2.0s b.) What is its rotational speed at the end of that time interval?

a.) 11 radians b.) 10 rad/s

What is the vector product of A= 2i+3j+1k and B=1i-3j-2k?

-3i+5j-9k

A typical laboratory centrifuge rotates at 4000 rpm (revolutions per minute). What is the Period T of one revolution, in seconds?

0.015 seconds

Two Ice Skaters push off against one another starting from a stationary position. The 45.0kg skater acquires a speed of 0.375 m/s. What speed does the 60.0-kg skater acquire? Assume that any other unbalanced forces during the collision are negligible.

0.281 m/s

What is the kinetic energy of a 120-cm thin uniform rod with a mass of 450 g that is rotating, about an axis perpendicular to the rod and through its center at 3.60 rad/s?

0.350 J

A 17.5 cm-diameter record rotates with a period of T=1.33s. What is the speed (v) of a bug sitting on the edge of the record?

0.413 m/s

A car travels at a steady rate 40.0 m/s around a horizontal curve of radius 200 m. What is the minimum coefficient of static friction between the road and the car's tires that will allow the car to travel at this speed without sliding

0.816

A building has light fixtures consisting of small 2..35 kg bulbs hanging from the ceiling at the end of light, thin cords of an unknown length. When given a small bump, the lights swing back and forth with a period of 2.50s. What is the length L of the cords?

1.55m

3.00 moles of oxygen gas is distilled into an evacuated 600 cm^3 container at 150 C. What is the pressure of the gas?

1.76x10^7 Pa

A potter's wheel has the shape of a solid uniform disk of mass 7.0 kg and radius 0.65 m. It spins about an axis perpendicular to the disk at its center. A small 2.1-kg lump of very dense clay is dropped onto the wheel at a distance 0.41 m from the axis. What is the rotational inertia of the system about the axis of spin?

1.8 kg*m^2

In the figure, the horizontal lower arm has a mass of 2.8-kg and its center of gravity is 12 cm from the elbow joint pivot. How much force F_M must the vertical extensor muscle in the upper arm exert on the lower arm to hold a 7.5kg shot put?

1000 N

During a collision with a wall, the velocity of a 0.200 kg ball changes fro 20 m/s toward the wall to 12.0 m/s away from the wall. IF the time the ball was in contact with the wall was 60.0 ms, what was the magnitude of the average force applied to the ball?

107 N

An unsuspecting 23.0 kg child sitting atop a straight, frictionless slide inclined 38.0 degrees above the horizontal begins to slide down. If the slide is 10.0 m long, what is the child's speed Vf at the botton?

11.0 m/s

A plastic block has dimensions 2.00 cm x 3.00 cm x 4.00 cm. It has a mass of 30.0 g. What is its density in kg/m^3

1250 kg/m^3

A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30, and the coefficient of kinetic friction is 0.20. What horizontal force must be exerted on the box to cause it to start sliding to the surface?

160 N

A copper telephone wire is stretched taut between two pole 165-m apart on a cold -20.0 C day. Find the new length of the wire on a hot 35.0 C summer day. (The coefficient of thermal expansions of copper is 17x10^-6 C^-1)

165.15m

A pilot traveling at a speed of v= 300 m/s enters a circular turn.If the centripetal acceleration the pilot experiences is 48 m/s2, what is the radius of the circular turn?

1875 m

Briefly explain Netwon's 3 Laws of Motion

1st law- inertia, an object at rest, and an object in motion will stay constant, uniform motion unless acted on by an outside force. 2nd law- F=ma 3rd law- For every action there is an equal and opposite reaction F_{12}=F_{21}

A 72.0-kg person pushes on a small doorknob with a force of 5.00 N perpendicular to the surface of the door. The doorknob is located 0.800 m from the axis of the frictionless hinges of the door. The door begins to rotate with an angular acceleration of 2.00 rad/s^2. What is the moment of inertia of the door about the hinges?

2.00 kg*m^2

What is the magnitude of the gravitational force that two small 7.00-kg spheres exert on each other when they are 35.0 cm apart? (G= 6.67 x 10^-11 N*m^2/kg^2)

2.67 x 10 ^-8 N

A force on a particle depends on position such that F(x)= (3.00 n/m^2)x^2 +(6.00 N/m)x for a particle constrained to move along the x-axis. What word is done by this force on a particle that moves from x=0 m to x= 2.00 m?

20.0 J

A sewing machine needle moves up and down in simple harmonic motion with an amplitude of 1.27 cm and a frequency of 2.55 Hz. What is the maximum speed of the top of the needle?

20.35 cm/s

With what minimum speed must a ball be thrown straight up in order to reach a height of 25.0 m above the launch position?

22.15 m/s

A 50-kg box is being pushed along a horizontal surface. The coefficient of static friction between the box and the ground is 0.65, and the coefficient of kinetic friction is 0.35. What horizontal force must be exerted on the box for its acceleration to be measured as 1.2 m/s^2

230 N

A car starts from rest at a stop sign. It accelerates at 4.00 m/s^2 for 6.00 seconds, coasts for 2.00 seconds, and then slows at a rate of 3.00 m/s^2 to come back to a stop at the next stop sign. What is the maximum speed the car achieves between the stop signs?

24.0 m/s

A child is riding a merry-go-round that is turning at 7.18 rev/min. If the child is standing 4.65 m from the center of the merry-go-round, how fast is the child moving?

3.50 m/s

While preparing for a NASA mission, you draw a line 6.40 meters above the launching pad, and measure that is takes 1.30 s for a rock to drop from the line to the ground when released from rest. You repeat this measurement on Mars, but now the rock dropped from 6.40 m above the ground takes 1.85s to land. What is the magnitude of the acceleration due to gravity on Mars?

3.74 m/s^2

A rigid container holds3.20 moles of an ideal gas at an absolute pressure of 1.92x10^5 Pa and a temperature of 40.0 C. The container will explode if it reaches a pressure of 2.48x10^5 Pa. What maximum gas temperature does this correspond to?

404.5 K 131.1 Degrees C

A velocity vector has components 36 m/s westward and 22 m/s northward. What are the magnitude and direction of this vector? (For direction, be sure to specify where you are measuring the angle from.)

42.s m/s at 58.6 degrees West of North

An athlete stretches a spring an extra 40.0 cm beyond its initial length. How much energy has he transferred to the spring, if the spring constant is 52.9 N/cm

423 J

The brain of a T-Rex was 4.70m above the ground, based on fossil evidence. What is the pressure difference between the brain and the ankle of the T-rex which was 0.25 m above the ground? Assume dinosaur blood has a density of 1060 kg/m^3

46,274 Pa

A ferris wheel has a diameter of 10 m and makes one revolution in 8.0 seconds. A person weighing 670 N is sitting on one of the benches attached at the rim of the wheel. What is the apparent weight (that is, the normal force exerted on her by the bench) of the person as she passes through the highest point of her motion?

460 N

A uniform solid disk of radius 1.60 m and mass 2.30 kg rolls without slipping to the bottom of an inclined plane. If the angular velocity if the disk is 5.35 rad/s at the bottom, what is the height of the inclined plane?

5.61 m

The maximum acceleration a pilot can stand without blacking out is about 7.0 g. In an endurance test for a jet plane's pilot, what is the maximum speed he can tolerate if he spun in a horizontal circle of diameter 85 m?

54 m/s

A piece of aluminum with a mass of 1.00 kg and a volume of 3.70 x 10^-4 m^3 is suspended from a light cord and then completely immersed in a container of water. Determine the tension in the cord when the aluminum is immersed in the water.

6.18 N

Ball Bearings manufacturing requires the molten metal to fall through the air for a total of 4.00 seconds to solidify. If released with an upward velocity of 3.00 m/s, find the initial height above the ground the metal needs to be released from to stay in the air for 4.00 seconds.

66.5 m

A Ferris wheel rotates at a constant speed. At the top of the ride, what is the direction of the acceleration of the rider?

Downwards

Which temperature scale labels the boiling point of water at 373?

Kelvin

A container hold a mixture of light hydrogen and heavy radon gases at 100 C. Which of the following statements is true?

The hydrogen molecules have the greater average speed

What direction does the buoyant force on an object point? Why does it always point this direction?

Up. Pressure is greater at the bottom (deepest part) of an object.

A light block of mass m is tied beneath a heavy block of mass M. A student drops the system into free-fall. What is the tension in the rope after she lets go but before the block hits the ground?

Zero

The velocity vs. time graph below describes the motion of a particle from 0 to 12 seconds. The particle is located at x=3.0m at t=2.0 s. a.) find the particles acceleration at t=8.0s b.) find the particles position at t=8.0s

a.) 2.5 m/s^2 b.) 10 m

A centrifuge in a medical laboratory rotates at a rotational speed of 3600 rev/min. When switched off, it makes 50 complete turns at a constant rotational acceleration before coming to rest. a.) What was the magnitude of the rotational acceleration of the centrifuge as it slowed down? b.) In what time interval did the centrifuge come to rest after being switched off?

a.) 230 rad/s^2 b.) 1.7 s

For the record for the fastest recorded serve in tennis, the ball was launched from rest to a velocity of 73.2 m/s. Assume the racket is in contact with the tennis ball over a horizontal displacement of 10.0 cm and creates a constant acceleration. We can ignore gravity during this brief contact. a.) Find the acceleration a_x of the tennis ball during the serve. b.) Find the force F_x exerted by the racket on a 59.4 gram tennis ball.

a.) 26791 m/s^2 b.) 1591 N

A 750 g block is attached to a light spring and placed on a frictionless horizontal track. The block oscillates with a period of 1.67s and reaches a maximum speed of 1.35 m/s. Find the following quantities: a.) angular frequency b.) Amplitude

a.) 3.76 rad/s b.) 0.359m

a 650g block is attached to a light spring and placed on a frictionless horizontal track. The block oscillates at an angular frequency of w= 8.17 rad/s and has an amplitude of A=0.294m. Find the following: a.) Spring Constant b.) Total Mechanical energy

a.) 43.4 N/m b.) 1.875 J

A 175-kg rocket sled accelerates from rest at 45.0 m/s^2 for a total burn time of 5.00 seconds. a.) Find the displacement of the sled during the burn. b.)Calculate the net force acting on the sled during the burn.

a.) 562.5 m b.) 7875 N

The system is sitting motionless. You can assume that there is no friction between the ramp and mass 2. a.) Find the Tension in the rope b.) If the ramp is at an angle of 37 degrees, find m2

a.) 98 N b.) 16.6 kg

An athlete weighs 690 N in air and 42.0 N when weighed fully submerges in water. (pwater= 1000 kg/m^3) a.) What is the value of the buoyant force on the athlete when submerged in water? b.) What is the athlete's volume?

a.)648 N b.) 0.066 m^3

A floating log is seen to bob up and down 15 times in 60 seconds as uniformly spaced waves pass you by. What are the frequency f and the period T of the wave?

f=0.25 Hz T= 4.0s