Question

Warmup 4 Dr. Colbert two dim motion Due Wed. 23 PhysSpring2019 A ball is thrown initially at 20.0m/s in a direction of 60° above the horizontal. What are the initial horizontal and vertical components of velocity? Vx init Vy init- 2. For the ball thrown in problem 1, one of the four kinematic equations is used to determine the time i takes for the ball to reach the peak. Write out the equation first using symbols), and then plug in the numbers. DO NOT SOLVE DO NO ALGEBRA Kinematic equation: Equation with numbers: 3. What is the velocity of the ball from problem 1 at the peak height (careful-it is not zero)? 4. What is the average vertical speed for the time interval from launch until the ball is at the peak?

Answer 1

V_x IN = V co theta = 20 times cos 60 degree = 10 m/s v_y in = V sin theta = 20 times sin 60 degree = 17.32 m /s V = u + at kinetic equation Equation with no, O = 17.32 - 9.81 times t velocity at peak, V_peak = V_x rightarrow V_peak = 10 m /s t = 19.32/9.81 = 1.765 sec. V^2 = 4^2 cos rightarrow 0 = (17.32)^2/2 times 9.81 = 15.29 m Therefore Avg vertical speed V_avg = s/t = 15.29/1.765 = 8.66 m /s