Watson General Physics I Final

The magnitude of a unit vector is one. T/F

True

A projectile is launched from ground level at an angle of 30.0° above horizontal with a speed of 10.0 m/s. If the projectile is moving over level ground, what is the maximum height above the ground that the projectile reaches?

1.27 m

A 5 kg object moving with a speed of 10 m/s collides with a 4 kg objective moving with a velocity of 15 m/s in a direction 37 degrees from the initial direction of motion of the 5 kg object. What is the speed of the two objects after the collision if they remain stuck together?

12 m/s

A rock is dropped from a vertical cliff. The rock takes 3.00 s to reach the ground below the cliff. A second rock is thrown vertically from the cliff. It takes 2.00 s to reach the ground below the cliff from the time it is released. With what velocity was the second rock released?

12.3 m/s downward

The position of an object as a function of time is given by x = bt2 - ct, where b = 2.0 m/s2 and c = 6.7 m/s and x and t are in SI units. What is the instantaneous velocity of the object when t = 2.2 s?

2.1 m/s

The figure shows a block of mass m resting on a 20° slope. The block has coefficients of friction and with the surface of the slope. It is connected using a very light string over an ideal pulley to a hanging block of mass 2.0 kg. The string above the slope pulls parallel to the surface. What is the minimum mass m so the system will remain at rest when it is released from rest?

2.2 kg

The position of an object is given as a function of time as x(t) = (3.00 m/s)t + (2.00 m/s2)t2. What is the displacement of the object between t = 4.00 s and t = 5.00 s?

21.0 m

What is the mass of an object that experiences a gravitational force of 224 N near Earth's surface where g = 9.80 m/s^2?

22.9 kg

A rock is thrown at a window that is located 18.0 m above the ground. The rock is thrown at an angle of 40.0° above horizontal. The rock is released from a height of 2.00 m above the ground with a speed of 30.0 m/s. If the rock strikes the window on its upward trajectory, from what horizontal distance from the window was it released?

27.3 m

Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle with a radius of 600 m. At the bottom of the dive, the speed of the airplane is 150 m/s. What is the apparent weight of the 70-kg pilot at that point?

3300 N

A driver in a 1000-kg car traveling at 23 m/s slams on the brakes and skids to a stop. If the coefficient of friction between the tires and the level road is 0.80, how long will the skid marks be?

34 m

An object has a position given by = [2.0 m + (5.00 m/s)t] + [3.0 m - (2.00 m/s2)t2]. What is the magnitude of the acceleration of the object at time t = 2.00 s?

4.00 m/s^2

An airplane flies between two points on the ground that are 500 km apart. The destination is directly north of the origination of the flight. The plane flies with an air speed of 120 m/s. If a constant wind blows at 10.0 m/s due west during the flight, what direction must the plane fly relative to north to arrive at the destination?

4.78° east of north

A 600-kg car is going around a banked curve with a radius of 110 m at a steady speed of 30.5 m/s. What is the appropriate banking angle so that the car stays on its path without the assistance of friction?

40.8°

The only force acting on a 2 kg body as it moves out the positive x-axis is given by F = -(6x) N, where x is in meters. If the kinetic energy of the body at x = 2 m is 60 J, what is its kinetic energy at x = 3 m?

45 J

A 10 g bullet moving 1000 m/s strikes and passes through a 2 kg block initially at rest. The bullet emerges from the block with a speed of 400 m/s. To what maximum height will the block rise above its initial position?

46 cm

The curved section of a horizontal highway is a circular unbanked arc of radius 770 m. If the coefficient of static friction between this roadway and typical tires is 0.40, what would be the maximum safe driving speed for this horizontal curved section of highway?

55 m/s

A 2 kg block situated on a frictionless incline is connected to a light spring (k = 100 N/m). The block is released from rest when the spring is unstretched. The pulley is frictionless and has negligible mass. What is the speed of the block when it has moved 0.2 m down the plane?

60 cm/s

A child throws a ball with an initial speed of 8.00 m/s at an angle of 40.0° above the horizontal. The ball leaves her hand 1.00 m above the ground. How far from where the child is standing does the ball hit the ground?

7.46 m

In a carnival ride, passengers stand with their backs against the wall of a cylinder. The cylinder is set into rotation and the floor is lowered away from the passengers, but they remain stuck against the wall of the cylinder. For a cylinder with a 2.0-m radius, what is the minimum speed that the passengers can have so they do not fall if the coefficient of static friction between the passengers and the wall is 0.25?

8.9 m/s

A 2.4 kg ball falling vertically hits the floor with a speed of 2.5 m/s and rebounds with a speed of 1.5 m/s. What is the magnitude of the impulse exerted on the ball by the floor?

9.6 N-s

Vector A has a magnitude 5.00 and points in a direction 50.0° counterclockwise from the positive x axis. What are the x and y components of vector A?

Ax = 3.21 and Ay = 3.83

You are standing in a moving bus, facing forward, when you suddenly slide forward as the bus comes to an immediate stop. What force caused you to slide forward?

There is not a force causing you to slide forward.

If the acceleration of an object is negative, the object must be slowing down. T/F

False

If the rockets of a spaceship in outer space (far from all gravity) suddenly lose power and go off, the spaceship will gradually slow to a stop. T/F

False

Consider a particle moving with constant speed such that its acceleration of constant magnitude is always perpendicular to its velocity.

It is moving in a circle.

Suppose that a car traveling to the west (the -x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration in the x direction is correct?

Its acceleration is positive but its velocity is negative.

A girl attaches a rock to a string, which she then swings counter-clockwise in a horizontal circle. The string breaks at point P in the figure, which shows a bird's-eye view (as seen from above). Which path (A-E) will the rock follow?

Path B

The figure illustrates a uniform metal sheet shaped like a triangle, with a hole cut in the center. Where is the center of mass of this object, relative to the coordinate system shown?

Somewhere on the y-axis, where x = 0.

A ball is thrown directly upward and experiences no air resistance. Which one of the following statements about its motion is correct?

The acceleration is downward during the entire time the ball is in the air.

Consider a collision of two billiard balls in which they approach at an angle (i.e. not head-on). Which of the following statements is true about this collision?

The combined momenta in all directions are the same as before the collision.

For a conservative force, the work done against the force is transferred to the system as potential energy. If you push a wooden crate across rough ground with a force F over a distance d, what is the potential energy stored in the system due to this force?

There is no energy stored in the system due to the force F.

Two objects are thrown from the top of a tall building and experience no appreciable air resistance. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when they hit the street?

They are traveling at the same speed.

You stand on the edge of a very tall building with three rocks, which you are going to throw off the edge. You throw the first rock straight outwards, the second rock at an angle 60° above the horizontal, and the third rock 30° below the horizontal. If you throw all three rocks with the same initial speed, which will be moving the fastest when it hits the ground?

They will have the same speed.

If the graph of the position as a function of time for an object is a horizontal line, that object cannot be accelerating. T/F

True

Consider a space colonist on a far off planet. They are trying to lift a box tied to a rope from the ground to a first-floor window. Will it require more power to lift this box in two seconds or in two hours?

Two seconds.

An object is moving with constant non-zero acceleration along the +x-axis. A graph of the velocity in the x direction as a function of time for this object is

a parabolic curve.

A pilot drops a bomb from a plane flying horizontally at a constant speed. Neglecting air resistance, when the bomb hits the ground the horizontal location of the plane will

be over the bomb

Two objects are dropped (with zero initial speed) from a height h. If object A has twice the mass of object B, what can be said about the momentum of each just before they hit the ground? Ignore air resistance.

object A has twice the momentum pf object B.

When a car goes around a circular curve on a horizontal road at constant speed, what force causes it to follow the circular path?

the friction force from the road

You push on box G that is next to box H, causing both boxes to slide along the floor, as shown in the figure. The reaction force to your push is

the push of box G against you