A spring of force constant 800N/m has an extension of 5cm. The work done in extending it from 5cm to 15cm is? a) 8J b) 16J c) 24J

A force of 100N acts on a block at an angle of 53° with respect to the horizontal, as shown. As the block moves through a displacement of 4 m to the left, the work done on the block by the force is A) +320 Nm B) +240 Nm F C) zero Ax D) -240 Nm E) -3200 Nm O A O D O E

Mike is cutting the grass using a human-powered lawn mower. He pushes the mower with a force of 45 N directed at an angle of 41° below the horizontal direction. Calculate the work that Mike does on the mower each time he pushes it 9.1 m across the yard. A) 483J В 358 J c) 437 J D) 309 J

A cheetah can accelerate from rest to 7.4 m/s (about 18 m/h) in 1.8 seconds. How much average power does the cheetah generate during the acceleration phase of its motion if its mass is 51 kg?a) 1400 W. b) 1600 W. c) 1800 W. d) 2500 W. e) 2800 W.