Anderson Physics 195 Midterm 1 Review (Modules 1-7)

When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air. (T/F)

True

Two equal masses are hanging by ropes from either side of a lightweight frictionless pulley. The masses are at rest. The acceleration of each mass is...

0.0 m/s^2

If (vectors) A > B, under what condition is | A - B | = A - B?

Vectors A and B are in the same direction.

1 meter is approximately...

3 feet

Alice and Tom dive from an overhang into the lake below. Tom simply drops straight down from the edge, but Alice takes a running start and jumps with an initial horizontal velocity of 25 m/s. Neither person experiences any significant air resistance. Compare the time it takes each of them to reach the lake below.

Alice and Tom will reach the surface of the lake at the same time.

Two objects, each of weight W, hang vertically by spring scales. The pulleys and the strings attached to the objects have negligible weight, and there is no appreciable friction in the pulleys. The reading in each scale is...

W

If you set your car on cruise control to a certain speed and make a turn, the speed of the car will remain the same. Is the car accelerating? (Y/N)

Yes

Is there a gravitational force acting on the astronauts inside the International Space Station? (Y/N)

Yes

A 615 N student standing on a scale in an elevator notices that it reads 645 N. The student knows the elevator must be moving...

You cannot tell if it is moving upward or downward.

A fish weighing 16 N is weighed using two spring scales, each of negligible weight. What will be the readings of the scales?

Each scale will read 16 N.

A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s. The vector sum of all the forces acting this crate must point down the ramp. (T/F)

False

A person of mass m stands on a scale that is resting on the floor of an elevator car. If the elevator car is moving upward, then the reading on the scale will be greater than mg. (T/F)

False

An astronaut in a space station in orbit around the Earth feels weightless because the force of gravity on the astronaut is zero. (T/F)

False

If I add two vectors, the magnitude of their sum is always bigger than each vector individually. (T/F)

False

If a block is sliding along a horizontal wooden plank, then lifting one end of the plank will cause the force of gravity acting on the block to decrease in magnitude. (T/F)

False

If a box is at rest on a horizontal floor, then the magnitude of the force of static friction on the box is given by fs = MusN , where Mus is the coefficient of static friction between the box and the floor and N is the magnitude of the normal force exerted on the box. (T/F)

False

If a projectile is launched from ground level at time t = 0 with a launch angle of 45 degrees, then the projectile's horizontal velocity is zero at the top of its parabolic path. (T/F)

False

If the acceleration of an object is a constant 1.0 m/s^2, then the object's position-vs.-time graph will be a straight line. (T/F)

False

If the net force on an object is not zero, then the speed of the object must be changing. (T/F)

False

If two objects have the same velocity, then they must have the same speed. (T/F)

False

The direction of an object's acceleration vector is always the same as the direction of its velocity vector. (T/F)

False

Two blocks of equal mass are next to each other on a frictionless table. You push on the first block with force F causing both blocks to accelerate. True or False: The force on the second block is equal to F. (T/F)

False

The slope at a point on a position-versus-time graph of an object is...

Instantaneous Velocity

A mosquito collides head-on with a car travelling at 60 mph. Is the magnitude of the mosquito's acceleration larger than, smaller than, or equal to the magnitude of the car's acceleration?

Larger

A woman is straining to lift a large crate, without success because it is too heavy. We denote the forces on the crate as follows: P is the upward force the woman exerts on the crate, C is the vertical contact force exerted on the crate by the floor, and W is the weight of the crate. How are the magnitudes of these forces related while the woman is trying unsuccessfully to lift the crate?

P + C = W

When accelerating slowly from a stop sign, we can say that the propulsion force on a car is due to...

Static Friction

A rope is tied to the wall. You pull on it with a force of 100 N. The tension in the rope is T1. Now you play tug-of-war: a second person holds the other end of the rope and you both pull with a force of 100 N in opposite directions. The tension in the rope is now T2. Which of the following is true?

T1 = T2

If the eastward component of vector A is equal to the westward component of vector B and their northward components are equal. Which one of the following statements about these two vectors is correct?

The magnitude of vector A is equal to the magnitude of vector B.

A mosquito runs head-on into a truck. Splat! Which is true during the collision?

The mosquito exerts the same force on the truck as the truck exerts on the mosquito.

An object is moving forward with a constant velocity. Which statement about this object MUST be true?

The net force on the object is zero.

Two objects have masses m and 5m, respectively. They both are placed side by side on a frictionless inclined plane and allowed to slide down from rest. What is the result?

The two objects reach the bottom of the incline at the same time.

Exactly two forces, F1 and F2, act on an object of mass m. If F2 > F1, then the object will accelerate. (T/F)

True

If a block is sliding along a horizontal wooden plank, then lifting one end of the plank will cause the force of kinetic friction acting on the block to decrease in magnitude. (T/F)

True

If a projectile launched from ground level at time t = 0 takes 4 seconds to hit the ground, then its acceleration was the same at time t = 1 s as it was at time t = 3 s. (T/F)

True

If a projectile launched from ground level at time t = 0 takes 4 seconds to hit the ground, then the projectile gains more height during its first second of flight (that is, from time t = 0 to t = 1 s) than during its second second (that is, from time t = 1 s to t = 2 s). (T/F)

True

It is possible for three vectors, none of which has magnitude zero, to add up to give the zero vector. (T/F)

True

The magnitude of a vector can never be less than the magnitude of one of its components. (T/F)

True

The magnitude of a vector is independent of the coordinate system used. (T/F)

True

Suppose a highway curve is properly banked to eliminate friction for a speed of 45 mph. If your tires were bald and you wanted to avoid sliding on the road, you would have to drive...

at exactly 45 mph

Suppose the force of the air drag on an object is proportional to the speed of the object and in the direction opposite the object's velocity. If you throw an object upward, the magnitude of its acceleration is greatest...

right after the object is released.

For general projectile motion, when the projectile is at its highest point of trajectory...

its velocity is perpendicular to the acceleration

A brick is resting on a rough incline. The friction force acting on the brick, along the incline, is...

less than the weight of the brick.

When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal speed. Once he has reached terminal speed...

the force of air drag on him is equal to his weight.

Alice and Tom dive from an overhang into the lake below. Tom simply drops straight down from the edge, but Alice takes a running start and jumps with an initial horizontal velocity of 25 m/s. Neither person experiences any significant air resistance. Just as they reach the lake below...

the speed of Alice is larger than that of Tom.

A ball is tossed vertically upward, at its highest point...

velocity is zero, acceleration is downward, and gravity is also downward.

A box slides down a frictionless plane inclined at an angle θ above the horizontal. The gravitational force on the box is directed...

vertically.