Exam 2: The Laws of Physics Are Universal Newtonian Mechanics

A plane in a certain circular holding pattern banks at an angle of $8^{\circ}$ when flying at a speed of $150 \mathrm{mi} / \mathrm{h}$ . If a second plane flies in the same circle at $300 \mathrm{mi} / \mathrm{h}$ , what is its banking angle?

You are driving $5 \mathrm{ft}$ or so behind a pickup truck (don't actually try such a stupid tailgating stunt, of course!). A jostled crate tips off the back of the truck with only a very small backward velocity. The crate will not hit your car until after it hits the road, regardless of your speed.

The radius of the earth's (almost circular) orbit around the sun is $150,000,000 \mathrm{~km}$ , and it takes $1 \mathrm{y}$ for the earth to go around the sun. Imagine that a certain satellite goes in an almost circular orbit of radius $15,000 \mathrm{~km}$ around the earth (this radius is 10,000 times smaller than the earth's orbital radius around the sun). What is the period of this orbit?

For a swinging pendulum, the maximum angle that the pendulum's string makes with the vertical corresponds to what in the pendulum solution $\phi=A \cos (\omega t+\theta)$ ?

The diagram below shows a top view of the moon's nearly circular orbit around the earth. The moon orbits the earth at a nearly constant speed. At the point shown, use the arrow choices shown to the right to indicate the direction of -The moon's acceleration.

Suppose a baseball travels $425 \mathrm{ft}(130 \mathrm{~m})$ from where the batter hits it to where it lands in the stands. The ball's velocity makes an angle of $40^{\circ}$ with respect to the horizontal as the ball leaves the bat. Suppose we first calculate the ball's initial speed ignoring drag and find it to be $\left|\vec{v}_{0}\right|$ . Including drag might plausibly require a higher initial speed for the ball to travel the same horizontal distance. On the other hand, by slowing down the ball's vertical motion, including drag will increase the ball's flight time, allowing the ball the same distance with a slower horizontal velocity. So if we include drag, for the ball to fly the same horizontal distance will we need

Figure N1.6 shows the acceleration for an object moving clockwise around the circle. If the object moves counterclockwise around the circle, its acceleration points outward instead of inward.

The drawing below is supposed to be a free-body diagram of a box that sits without slipping on the back of a truck that is moving to the right but is slowing down. Is the diagram correct?

A child $C$ pulls on a wagon $W$ , using a string $S$ ; the wagon moves forward at a constant speed as a result. The third-law partner to the forward force exerted on the wagon is which of the following forces? ( $\mathrm{R}=$ road.)

Assume that the coefficient of static friction between your car's tires and a certain road surface is about 0.75 . Your car can climb a $45^{\circ}$ slope.

Two stars, one with radius $r$ and the other with radius $3 r$ , orbit each other so that their centers of mass are $25 r$ apart. Assume that the stars have the same uniform density. This system's center of mass is inside the larger star.

A box $B$ sits in the back of a truck $T$ as the truck slows down for a stop (the box remains motionless relative to the truck). What is the appropriate symbol for the horizontal force that the contact interaction between the box and the truck exerts on the truck?

A box sits at rest on an inclined plank. How do the magnitudes of the normal force and the gravitational force exerted on the box compare? (Hints: What is the box's acceleration? Draw a free-body diagram!)

A physicist and a chemist are playing tug-of-war. For a certain length of time during the game, the participants are essentially at rest. During this time, each person pulls on the rope (which can be treated as an ideal string) with a force of $350 \mathrm{~N}$ . What is the tension on the rope?

Consider an orbit where $r_{c}=1 \mathrm{AU}$ and $b=2 \mathrm{AU}$ . What kind of orbit is this?

An object's $x$ -velocity can be positive at the same time that its $x$ -acceleration is negative.

An object can have a constant speed and still be accelerating.

A glider on an air track is connected by a spring to the end of the air track. If it takes $0.30 \mathrm{~s}$ for the glider to travel the distance of $12 \mathrm{~cm}$ from one turning point to the other, its amplitude is

An object travels halfway around a circle at a constant instantaneous speed $|\vec{v}|$ . What is the magnitude $|\vec{\psi}|$ of its average velocity during this time interval?

Suppose you throw a ball vertically into the air. At the exact instant that the ball reaches its highest position, select from the choices below the most accurate description of -The gravitational force on the ball.