Q. A projectile is fired straight upward at 141 m/s. How fast is it moving at the instant it reaches the tip of its trajectory? Suppose instead that it were fired upward at 45 degrees. What would be its speed at the tip of its trajectory?

Q. An alpha particle (charge 2e) is sent at high speed toward a gold nucleus. The electric force acting on the alpha particle is 91 N when it's 2.00 x 10^(exponent)-14m away from the gold nucleus What is the charge on the gold nucleus, as a whole number multiple of e? (e= 1.60 x 10^-19. kc= 8.99 x 10^9).