A rock is thrown from a bridge at an angle $30^{\circ}$ below horizontal. a. Immediately after the rock is released, is the magnitude of its acceleration greater than, less than, or equal to $\mathrm{g}$ ? Explain. b. At the instant of impact, is the rock's speed greater than, less than, or equal to the speed with which it was thrown? Explain.

A high-speed drill rotating ccw at 2400 rpm comes to a halt in 2.5 s. a. What is the magnitude of the d rill’s angular acceleration? b. How many revolutions does it make as it stops?

A magnetic computer disk $8.0 \mathrm{~cm}$ in diameter is initially at rest. A small dot is painted on the edge of the disk. The disk accelerates at $600 \mathrm{rad} / \mathrm{s}^2$ for $\frac{1}{2} \mathrm{~s}$, then coasts at a steady angular velocity for another $\frac{1}{2} \mathrm{~s}$. What is the speed of the dot at $t=1.0 \mathrm{~s}$ ? Through how many revolutions has the disk turned?

Communications satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the earth rotates. These are called geosynchronous orbits. The radius of the earth is $6.37 \times 10^{6} \mathrm{m}$, and the altitude of a geosynchronous orbit is $3.58 \times 10^{7} \mathrm{m}(\approx 22,000 \text { miles })$. What are (a) the speed and (b) the magnitude of the acceleration of a satellite in a geosynchronous orbit?

As the earth rotates, what is the speed of (a) a physics student in Miami, Florida, at latitude $26^{\circ}$, and (b) a physics student in Fairbanks, Alaska, at latitude $65^{\circ}$? Ignore the revolution of the earth around the sun. The radius of the earth is 6400 km.

A car starts from rest on a curve with a radius of $120 \mathrm{~m}$ and accelerates at $1.0 \mathrm{~m} / \mathrm{s}^2$. Through what angle will the car have traveled when the magnitude of its total acceleration is $2.0 \mathrm{~m} / \mathrm{s}^2$ ?