. A rock of mass 0.5 kg is launched straight up. A constant upward force of 405 N acted on the rock while it moved 25 cm upward starting from rest. Ignore air resistance. a. Find the launce speed using the work-energy theorem [use g = 10 m/s2). b. Using energy ideas, find the maximum height above the launch point (25 cm) the rock will reach.​

In which situation is the acceleration of a car negative? question 5 options: a)the velocity of a car was 75 km/hr over 4 hours. b)the velocity of a car reduced from 50 km/hr over one minute. c)the velocity of a car increased from 40 km.h to 75 km/h over 15 minutes. d)the velocity of a car was 45 km/hr at 2: 00pm and at 4: 00pm its velocity was 85 km/ht.