1.Two cars traveling with the same speed move directly away from one another. On car sounds a horn whose frequency is 185 Hz and a person in the other car hears a frequency of 167 Hz. What is the speed of the cars?____m/s?
Question 2-3 refer to the following situaion. A projectile of mass M = 1000 kg is launched with an initial speed of 43 m/s at an initial angle of 24°. When it reaches the top of its arc, it explodes into two pieces. The first has a mass of ml = 200 kg and has a velocity after the explosion v = 0z -15ÿ, m/s and the second has a mass of m2 = 800 kg.
2. Consider the projectile before the explosion. Using either kinematics or conservation of energy, find vx and vy for the object at the top of its arc? What height does it reach (Δy)? How far from the launch point does it travel (Δx)? (Hint: What is true about an object's motion at the top of its arc?)
3. Write down expressions for the conservation of momentum for the object before and after the explosion. What are the final velocities of the two objects immediately after the explosion? (You are given one of these already!)
4.
5. An electromagnetic wave of wavelength 435nm is traveling in vacuum in the -z-direction. The electric field has amplitude 2.70×10-3V/m and is parallel to the x-axis.
6. Mantles for gas lanterns are made of thorium, because it forms an oxide that can survive being made incandescent for long periods of time. Natural thorium is almost 100% 232Th, with a half-life of 1.405 ? 1010 y. If the average lantern mantle contains 380 mg of thorium, what is its activity?