H2.3 3/3 points (graded) Att = 10 s, a particle is moving from left to right with a speed of 5.0 m/s. Att = 20 s, the particle is moving right to left with a speed of 8.0 m/s. Assuming the particle's acceleration is constant, determine a, its acceleration in m/s2. Give your answer to two significant figures without units. -1.3 v -1.3 b. its initial velocity in m/s Give your answer to two significant figures without units. 18 V 18 c. the instant (in sec) when its velocity is zero. Give your answer to two significant figures without units. 13.8 V 13.8 Submit Siwww answer H2.4 1/1 point (graded) The velocity of a bullet is reduced by 50% after entering 230 cm deep inside of a wooden block. What is the total distance the bullet penetrates the block before coming to stop? Assume constant acceleration. Give your answer in cm to three significant figures without units 306.67 V Submit Show answer Homework due Nov 17, 2022 10:00 PST Completed H2.5 1/1 point (graded) A rescue helicopter is hovering over a person whose boat has sunk. One of the rescuers throws a life preserver straight down to the victim with an initial velocity of 1.2 m/s and observes that it takes 2.0 s to reach the water. How high above the water was the preserver released? Note that the downdraft of the helicopter reduces the effects of air resistance on the falling life preserver, so that an acceleration equal to that of gravity is reasonable. Give your answer in meters to two significant figures without units. 22.02 V