1. In her Mustang, Kelly rounds a curve onto a straight section of country road while traveling at 45 mph, only to find a fully loaded manure spreader completely blocking the road 37 m ahead of her. Startled, she travels at a constant velocity for 0.80 s of reaction time, then hits the brakes and slows with a constant acceleration so that she manages to stop just short of the spreader. With the same reaction time and acceleration, if she had raced around the corner at 60 mph instead of 45 mph, (a) How fast would she have been going when she hit the spreader? (b) How much time would she have for her life to flash before her eyes from the time she first sees the spreader until she hits it?
4. Sam heaves a 16-lb shot straight upward, giving it a constant upward acceleration from rest of 45.0 m/s2 over a distance of 64.0 cm. He releases it 2.20 m above the ground. (a) What is the speed of the shot when he releases it? (b) How high above the ground does it go? (c) How much time does he have to get out of its way before it returns to the height of the top of his head, 1.83 m above the ground?
The solution answers two questions on impact, speed and acceleration.