Physics Final Semester 1

A candy shop sells a pound of chocolate for 8.99$. What is the price of 2 kg of chocolate at the shop?

$39.60

During the construction of a high rise building, a 2 kg block is vertically lifted 20 m from the surface of the earth. To one sig fig, what is the change in the gravitational potential energy of the block?

+400 J

A 2.5 kg block of ice is sliding across a frozen pond at 8 m/s. A 12.25 N force is applied in the direction of motion. After the ice block slides 60 m, the force is removed. The work done by the applied force is...?

+735 J

An elevator is moving upward with a speed of 11 m/s. 3 seconds later, the elevator is still moving upward, but its speed has been reduced to 5 m/s. What is the acceleration of the elevator during the 3 second interval?

-2 m/s^2

A truck moves 70 m west, then moves 120 m east, and finally moves west again a distance of 90 m. If east is chosen as the positive direction, what is the truck's resultant displacement?

-40 m

A wheel, originally rotating at 126 rad/sec decelerates to 98 rad/sec while going through 628 radians. What is its angular acceleration?

-5 rad/sec^2

What is the momentum change of an .8 kg tennis ball that hits a wall at .55 m/s, and bounces back at .45m/s?

.8 kg m/s

An object moves 20 m east in 30 s and then returns to its starting point taking an additional 50 s. If west is chosen as the positive direction, what is the sign associated with the average velocity of the object?

0 (no sign)

A 4-kg mass has a speed of 6 m/s on a horizontal frictionless surface. The mass collides head-on and elastically with an identical 4-kg mass initially at rest. The second 4-kg mass then collides head-on and inelastically to a third 4-kg mass initially at rest. The final speed of the first 4-kg mass is...? The final speed of the two 4-kg mas that stick together is...?

0 m/s; 3 m/s

A 1.3 kg ball is coming straight at a 75 kg soccer player at 13 m/s who kicks it in the opposite direction at 22 m/s with a force of 1200 N. How long are his foot and the ball in contact?

0.038 sec

A boy throws a rock with an initial velocity of 2.15 m/s at 30 degrees above the horizontal. If air resistance is negligible, how long does it take for the rock to reach the maximum height of its trajectory?

0.110 sec

On a park ride, passengers are seated in a horizontal circle of radius 3.75 m. The seats begin from from rest and are uniformly accelerated for 21 secs to a max rotational speed of 1.4 rad/sec. What is the tangential acceleration of the passengers during the first 21 secs of the ride?

0.25 m/s^2

An apple crate with a weight of 355 N accelerates along a frictionless surface as the crate is pulled with a force of 14.5 N. What is the horizontal acceleration of the crate?

0.4 m/s^2

What is 0.674 divided by 0.74 to the proper number of sig figs?

0.91

A ball moves with a constant speed of 1 m/s around a circle of radius 0.25 m. What is the time of one revolution?

1.6 sec

0.0001776 can also be expressed as

1.776 X 10^-4

What is the earth's angular velocity around the sun? Assume a perfectly circular orbit, and that 1 year = 365.0 days.

1.99 x 10^-7 rad/sec

Estimate how many pennies would you have to stack to reach an average 8-foot ceiling from the floor.

10^3

A train approaches a small town with a constant velocity of 28.6 m/s. The operator applies the brake, reducing the train's velocity to 11.4 m/s. If the average acceleration of the train during breaking is -1.35 m/s^2, for what elapsed time does the operator apply the brake?

12. 7 sec

A string is wrapped round a pulley of radius 0.10 m and moment of inertia 0.15 kg m^2. The string is pulled with a force of 18 N. What is the magnitude of the resulting angular acceleration of the pulley?

12.0 rad/sec^2

An 810-kg car accelerates from rest to 27 m/s in a distance of 240m. What is most nearly the magnitude of the net force acting on the car?

1230 N

During the time a compact disc accelerates from rest to a constant rotational speed of 49.95 rad/sec, it rotates through an angular displacement of 9.9 rad. What is the angular acceleration of the CD?

126 rad/sec^2

A bicycle wheel of radius 0.7 m is turning at an angular speed of 6.3 rad/sec as it rolls on a horizontal road without slipping. How far will the wheel roll down the road in 3 sec?

13.2 m

A car accelerates from 10 m/s to 30 m/s at a rate of 3 m/s^2. How far does the car travel while accelerating?

133 m

A car on a roller coaster starts at zero speed at an elevation above the ground of 26 m. It coasts down a slope, and then climbs a hill. The top of the hill is at an elevation of 16 m. What is the speed of the car at the top of the hill?

14 m/s

An astronaut weighs 60 N in orbit some distance from the center of the earth. If she moved 2 times as far from the center of the earth, her weight would become...?

15 N

A 5 N force acts on an 8 kg object for 3 sec. What impulse is given to the object?

15 Ns

A string is wrapped around a pulley of radius 0.05 m and moment of inertia 0.2 kg m^2. If the string is pulled with a force F, the resulting angular acceleration of the pulley is 4 rad/sec^2. Determine the magnitude of the force F.

16 N

A football is kicked with a speed of 18 m/s at an angle of 25 degrees to the horizontal. What is the horizontal component of the initial velocity of the football? The vertical component? How long is the football in the air? How far does the football travel horizontally before it hits the ground?

16.3 m/s; 7.6 m/s; 1.6 sec; 25 m

A ball is pushed with an initial velocity of 4.0 m/s. The ball rolls down a hill with a constant acceleration of 1.6 m/s^2. The ball reaches the bottom of the hill in 8 seconds. Which is most nearly the ball's velocity at the bottom of the hill?

17 m/s

A 200 kg car moving at 6 m/s collides with a 400 kg car at rest. If the collision is inelastic, what is the velocity of the two cars tangled together after the collision?

2 m/s

A gymnast leaves a trampoline with a velocity of 6.7 m/s upward. What will be the max height she reaches?

2.3 m

An arrow is shot upwards with an initial velocity of 15 m/s upwards. How much time elapses before the velocity is 8 m/s downward?

2.35 sec

A bird, accelerating from rest at a constant rate, experiences a displacement of 56 m in 22 s. What is the average velocity?

2.5 m/s

A park ranger wanted to measure the height of a tall tree. The ranger stood 9.5 m from the base of the tree; and he observed that his line of sight made an angle of 64.6 degrees above the horizontal as he looked at the top of the tree. What is the height of the tree?

20 m

A projectile is fired at an angle of 60 degrees above the horizontal with an initial speed of 20 m/s. What is the magnitude of the horizontal component of the projectile's displacement at the end of 2 seconds?

20 m

The kinetic energy of an 1100 kg truck is 2.43 x 10^5 J. What is the speed of the truck?

21 m/s

A 22-kg child steps onto a scale and the scale reads 216 N. What is the magnitude of the normal force acting on the child?

216 N

At a horizontal distance of 45 m from a tree, the angle of elevation from the ground to the top of the tree is 26 degrees. How tall is the tree?

22 m

Convert a speed of 4.50 km/h to units of ft/min

246 ft/min

A bat strikes a 0.15 kg baseball pitched at 40m/s. The bat reverses the ball's direction and gives it a speed of 50 m/s. What average force does that bat apply to the ball if they are in contact for 0.054 sec?

250 N

0.254 m diameter circular saw blade rotates at a constant angular speed of 234 rad/sec. What is the tangential speed of the tip of a saw tooth at the edge of the blade?

29.7 m/s

A rock is thrown straight up with an initial velocity of 24.5 m/s. What maximum height will the rock reach before starting to fall downward?

30.6 m

Ed is pulling a wheeled suitcase across the floor. He pulls it with a force of 45 N directed at an angle of 41 degrees above the horizontal direction. Calculate the work that Ed does on the suitcase in pulling it 9.1 m.

310 J

Mt. Everest is more than 8,000 m high. How fast would an object be moving if it could free fall to sea level after being released from an 8,000-m elevation? (ignore air resistance, assume g is constant.)

396 m/s

The Roman Empire used a unit of measurement called a cubit, equal to 44.5 cm. Convert 2 meters to cubits.

4.49 cubits

A bicycle travels 35 m along a circular track of radius 7.5 m. What is the angular displacement in radians of the bicycle from its starting position?

4.7 rad

City A lies 30 km directly south of city B. A bus, beginning at city A travels 50 km at 37 degrees north of east to reach city C. How far, and in what direction must the bus go from city C to reach city B?

40km, west

A worker pushed a wheelbarrow 5 m across a level surface with a constant horizontal force of 50 N. Friction applies a backwards force of 41 N. What net work is done on the wheelbarrow?

45 J

What is the weight of a 5-kg bag of sand on the surface of the earth?

49.0 N

A net force F is required to give an object with a mass, m, an acceleration, a. If a net force 8F is applied to an object with a mass 2m, what is the acceleration on this object?

4a

The work needed to accelerate a car to 10 m/s from rest is...?

4x the work needed to accelerate to 5 m/s from rest

When the net force that acts on a hockey puck is 250 N, the puck accelerates at a rate of 50 m/s^2. Determine the mass of the puck.

5 kg

A drone helicopter with a mass of 250 kg is cruising at a speed of 25 m/s at an altitude of 185 m. What is the total mechanical energy of the helicopter?

5.31 x 10^5 J

A rock is kicked horizontally at a speed of 10 m/s from the edge of a cliff. The rock strikes the ground 55 m from the foot of the cliff of height H. How long is the rock in the air? What is the value of H, the height of the cliff.

5.5 sec; 150 m

a 1500 kg automobile traveling with a speed of 55 km/hr westward makes a head-on collision with an 1800 kg automobile traveling with a speed of 35 km/hr traveling east. The automobiles lock together during the collision and move together with a final speed, v. Find v.

5.9 km/hr west

A cart is given an initial velocity of 5 m/s and experiences a constant acceleration of 2 m/s^2. What is the cart's displacement during the first 5 s of its motion?

50 m

A merry-go-round is accelerated uniformly from rest and attains an angular speed of 4 rad/sec in the first 10 seconds. If the net applied torque is 2000 Nm, what is the moment of inertia of the merry-go-round?

5000 kg m^2

A quarterback throws a pass at an angle of 35 degrees above the horizontal with an initial speed of 25 m/s. The ball is caught by the receiver 2.55 seconds later at the same height it was thrown from. Determine the distance the ball was thrown.

52 m

What is the momentum of a 373 kg bumper car moving at 1.5 m/s.

560 kg m/s

A 2.3 kg object traveling at 6.1 m/s east collides head-on with a 3.5 kg object traveling in the opposite direction at 4.8 m/s. The 3.5 kg object recoils east at 3.89 m/s, what is the final speed of the 2.3 kg object?

7.1 m/s

A block weighing 20 N is being pushed across a horizontal table by an 18 N force. If the coefficient of kinetic friction between the block and table is 0.135, find the acceleration of the block.

7.5 m/s^2

What is the sum of 1.53 + 2.786 + 3.3 written with the correct number of sig figs?

7.6

An airplane is flying with a velocity of 7.5 m/s east. A man dashes across the wing with a velocity of 2.5 m/s south. Which is most nearly the magnitude of his velocity as seen by someone on the ground?

8 m/s

A 60 kg skater begins a spin with an angular speed of 6 rad/sec. By changing the position of her arms, the skater decreases her moment of inertia by 25%. What is the skater's final angular speed?

8.0 rad/sec

An indoor track is to be designed such that each end is a banked semi-circle with a radius of 24 m. What should the banking angle be for a person running at a speed v=6 m/s?

8.7 degrees

A car traveling at 40 m/s rounds a curve so that its centripetal acceleration is 20 m/s^2. What is the radius of the curve?

80 m