9. The displacement is given by x = 2 t^2 + t + 5. The acceleration at t = 2 s is (a) 4 m/s2
(b) 8 m/s2
(c) 10 m/s2
(d) 15 m/s2

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j ?

Ahowler monkey is the loudest land animal and, under some circumstances, can be heard up to a distance of 4.6 km. assume the acoustic output of a howler to be uniform in all directions and that the threshold of hearing is 1.0 × 10-12 w/m2. what is the acoustic power emitted by the howler

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?