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person is jumping from a height ℎ0 = 10 m with zero initial velocity and a cricket ball is thrown directly upward with an initial velocity 𝑣𝑣0 = 9.8 m/s at the same instant when time t = 0 s as shown in Fig. 1. Consider h = 11.5 m and 𝚤𝚤̂and 𝚥𝚥̂ to be the unit vectors along the X and Y axis. Gravity is acting along the -𝚥𝚥̂direction and the magnitude of gravitational acceleration is given by g = 9.81 m/s2 . The red dot on the person represents his center of mass.
(a) (4 marks) If the person and the cricket ball consist of a system, find the position and velocity of the center of mass of the system at time t = 0.5 s.
(b) (2 marks) If it takes 0.01 seconds for the person to come to complete rest when he hits the ground, calculate the average force acting on the person.
(c) (4 marks) Now consider when the person hits the ground, he bends his knees such that the center of mass of his body is lowered by 15 cm. If the maximum force that the bone of his legs can withstand is 50000 N, will he break his legs?
A plane flying due north at 100 m/s is blown by a strong wind at 500 m/s due east. What is the plane's resultant velocity?
The sound intensity level of a racing car at a distance of 10 m is 130 dB. Assume that the racing car like a small point source and ignore the effects of absorption and reflection. (a) What is the power of the sound emitted by the car? (b) What is the sound intensity at a distance of 10 m from the car? (c) What is the sound intensity due to the car at a distance of 1.0 km from the car? (d) At what distance from the car would the sound intensity fall to the threshold of hearing
A siren produces a sound intensity level of 90 decibel at a distance of 8.0 m.
assume that the siren acts as a point source of sound.
a. What is the sound intensity at a distance of 6.0m from the siren?
b. What is the power of the sound emitted by the siren?
c. What is the sound intensity level at a distance of 16.0 m from the siren?
A ball is thrown upward with an initial velocity of 10m/s. how high does the ball rise? and what is the total time flight
A flywheel initially rotating at 600 rpm is bought to a stop by a constant torque in 15 a. How many revolutions does the flywheel make before coming to stop
A 10N force is applied to a 5kg object resulting in an acceleration of 0.5m/s2. What is the force of friction acting on that object?
A 2kg cart experiences three forces a 10N pull to the left, a 10N pull to the right and then some other unknown pull. If the positive direction is to the right, and the carts accelerarion is 2m/s/s what us unknown force
Two 10 kg spheres experience a 4.17 * 10-10 N force. How far apart are their centers?
Cale has decided to soup up his bicycle by adding rocket propulsion to the
wheels. While testing his new rocket bike, he strikes a tuning fork tuned to
650Hz. As he travels towards Zander, Zander hears a frequency of 1600Hz.
Determine the mach number of Cale’s rocket bike if the temperature is 24
oC.
