Question

Question # 13,15 and 16

s 12) A man drops a 10 kg object from a height of 100 m. What is the potential energy of Dthe ball at a height of 30 m? A man drops a 10 kg object from a height of 100 m. What is the kinetic energy of the ball at a height of 30 m? 2. 2 て 叮 A horizontal massless spring with a spring constant of 100 N/m is attached to a wall. The other end of the spring is attached to a 50 kg block on a frictionless surface. The spring is compressed 0.25 m and released. What is the potential energy of the block at x-0.25? 14) 2. 15 A horizontal massless spring with a spring constant of 100 N/m is attached to a surface. The spring is compressed 0.25 m and released. What is the maximum wall. The other end of the spring is attached to a 50 kg block on a frictionless oo speed of the block? SAS 18 A 10 kg ball moving at 5 m/s bounces off a 2 kg ball at rest. If the 2 kg ball is moving at 8.3 m/s after the bounce, how fast is the first ball moving? 24s 1 2

Answer 1

Answer : 13 ; Kinetic Energy = 70 J

mass of object = 10kg

Final velocity of the body when it reaches at height 30m

distance travelled by bodu is 70 m or 0.7m

v^2 = u^2 - 2as = 0 - {2*(-10)*0.7} = 14

So velocity just as it reaches the ground = (Square root of 14) m/s

Kinetic energy = 1/2*m*v^2 = 1/2*10*14 = 70 J

Answer :15

$\Delta$KE = $\Delta$PE

1/2mv² = 1/2kx²

mv² = kx²

v² = kx²/m

v² = 100 x 0.25²/50

v² = 0.125

v² = 0.354 m/s

Answer :16

momentum is conserved

m1u1 +m2u2 = m1v1 +m2v2

(10x 5) + ( 2 x 0) = (10 x v1 ) + ( 2 x 8.3)

10v1 = 33.4

v1 = 3.34 m/s