PHY 101 Module 2 mastery

Question 1 2/2pts Amarble is dropped from a toy drone that is 25 m above the ground, and slowly rising with a vertical velocity of 0.8 m/s. How long does it take the marble to reach the ground? 2345 Correct, the time of light for an object in free fal that has an initial vertical velocity can be determined by an application of the one-dimensional kit matic equations Question 2 22 An obiect s dropped from rest out of the window of a building, and the time to hit the ground is found to be 5 seconds. The same object is then dropped from rest out of a window twice as high above the ground as the original window. The time it takes the object to hit the ground i closest to 7s Correct, the time of light for an object dropped from rest, and in free fal is proportional to the square root of the height from which it was dropped

Question 3 2/2pts Aprojectie s launched from the ground with an initial speed of 20 m/s at an angle of geabove the horizontal. What is the horizontal component of this projectile’s velocity the instant before it strikes the ground? 1813ms Correct, the horizontal component of the velocity, which is obtained by multiplying the iitial speed by the cosine of the angle, is constant throughout the entire trip for projectile motion. Question 4 2/2pts Apotatois shot out of cylinder at an angle of 1 above the horizontal with an initial speed of 20 m/s. What is its maximum height? 175m Correct, the maximum height of a projectile can be found by finding the vertical component of the initial velocity, and then using the time-independent kinematic equation for vertical motion.

Question 7 2/2pts Aperson stands on a clff next to a cannon. He lights the fuse on the cannon, which fires a projectile horizontally off the cliff. At the exact instant that the projectile passes the lip of the ciff,a marble is dropped from free fall offthe clif. lgnoring all ar resistance, the time it takes the marble to hit the ground is _ the time it takes the projectile to ht the ground. the same as Correct, the two projectiles will land at the same time, since both have zero inital velocity in the vertical direction. Question 8 RS An obiect of unknown mass is dropped from rest from a height of 100 m above ground level. How long does. it take the object to reach the ground? 4525 Correct, the time of flight for an object in free fall can be determined by an application of the one- dimensional kinematic equations.

Question 9 2/2pts | Aprojectie s launched with an unknown inital speed at an angle of gg:above the horizontal. The projectile lands at the same height from which it was launched 200 m from the launch site. What was the initial speed? Correct, the range equation can be used to solve for the initial speed of a projectile. Question 10 22 The "stopping distance” i the distance needed for a car to come to rest, as it decelerates uniformly, from some initial velocity. Doubling the intial velocity of a car will have what effect on its stopping distance? The stopping distance is ncreased by a factor of 4. Correct, the stopping distance of an object quadruples since the time-independent kinematic equation shows that the stopping distance is directly proportional the square of the iniial velocity.