Question
are ocenectied o each odher as shown. The system is released from rest and the 1.00-kg box falls through a no-. The hce ofthe table s frictionless. What is the kinetic energy ofbxBjust before it reaches Two boxes Eistance of 1.0- the floor (a) 245J (b) 490J () 9.80 3.00 kg 29,4 J (e) 3921 B 1,00 1 1.00 Aaengecer is asked to d ng, child reaches a. the bottom does not exceed 6.01 playground slide bght thar the slide cn be that the speed a m's Determine se (2) 1.8m b) 29m (e) 14 m d) 45m S above a horizomtal surface. The acceleration due to gravity is 6 A biock of mas m is released Son res u the speed ef the mass at the boaem of the hoop (al The blbci sides slong the iside of a frictionliess cicular boop of radius R. Which one of the following expressions gives 2R 7. A ptysics smadent shoves a 0.50-ig block from the bodon of a frictionless 30.0 inclined plane. The student performs 4.0 J of work and the block slides a distance s along the incline before it stops. Determine the value of s. (a) 5.0cm (b) 16 (c) (d) 82cm 160cm (c) 330 cmm S. Am automobile approaches a burrier at a speed of 20ns along a level road. The driver locks the brakes at a distance of 50 m fom the burrier Whsinun coefficicnt of kinetic friction is required to stop the automobile before it hits the burrier? (a) 04 (b) 0s (c) 0.6 (3) 0.7 (c) 0.8
Explanation / Answer
here,
5)
mB = 1 kg
mA = 3 kg
the accelration of the system , a = mB * g /( mA + mA)
a = 1 * 9.81 /( 3 + 1) m/s^2
a= 2.45 m/s^2
the final speed , v = sqrt(2 * a * s)
v = sqrt(2 * 2.45 * 1) = 2.21 m/s
the kinetic energy of block B , KEb = 0.5 * mB * v^2
KEb = 0.5 * 1 * 2.21^2 J
KEb = 2.45 J
the kinetic energy is 2.45 J
