question archive A wooden box of mass 10
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A wooden box of mass 10. kg slides down a ramp from a height of 1.0 m onto a frictionless tabletop. It is brought to rest by a compressed spring. The spring constant is 1250 N/m. a) Calculate the maximum distance the spring is compressed. b) Determine the speed and acceleration of the block when the spring is compressed a distance of 14 cm.
Answers :
Part (a) Answer : The maximum compression in the spring will be : xmax = 0.3962 m = 39.62 cm
Part (b) Answer : The speed and the acceleration of the block will be :
Speed : v = 4.14 m/s
Acceleration : a = 17.5 m/s2
Step-by-step explanation
Here we have given :
Mass of the block : m = 10 kg
Height of the ramp : h = 1 m
And, Spring constant : k = 1250 N/m
Let the maximum compression in the spring be xmax.
Now, According to the conservation of energy : The potential energy stored in the spring at the maximum compression of the spring will be equal to the initial gravitational potential energy of the spring.
∴ (1/2) k (xmax)2 = m g h
∴ (1/2)(1250 N/m) (xmax)2 = (10 kg)(9.81 m/s2)(1 m)
∴ (xmax)2 = 0.15696 m2
∴ xmax = 0.3962 m = 39.62 cm
Therefore, The maximum compression in the spring will be : xmax = 0.3962 m = 39.62 cm
Part (b) Solution :
Here, Compression in the spring : x = 14 cm = 0.14 m
Now, According to the conservation of energy : PEspring + KEblock = GPEblock
∴ (1/2) k x2 + (1/2) m v2 = m g h
∴ (1/2) m v2 = m g h - (1/2) k x2
∴ (1/2) m v2 = (10 kg)(9.81 m/s2)(1 m) - (1/2)(1250 N/m)(0.14 m)2
∴ (1/2) m v2 = 85.85 J
∴ (1/2)(10 kg) v2 = 85.85 J
∴ v2 = 17.17 m2/s2
∴ v = 4.14 m/s
And, When the spring is compressed : The force acting on the block will be : Fnet = Fspring = k x
Since, Fnet = m a
∴ m a = k x
∴ (10 kg) a = (1250 N/m)(0.14 m)
∴ a = 17.5 m/s2
This acceleration will be negative acceleration : Because the spring will be opposing the motion of the block.
Please see the attached file for the complete solution