Blocks with different masses are pushed against a spring one at a time, compress
ID: 1435464 • Letter: B
Question
Blocks with different masses are pushed against a spring one at a time, compressing it different amounts. Each is then launched onto an essentially frictionless horizontal surface that then curves upward, still frictionless (Figure 1) . The table below shows the masses, spring compressions, and maximum vertical height each block achieves.
Mass m (g) : 50.0 , 85.2 , 126 , 50.0 , 85.2
Compression x (cm):2.40 , 3.17 , 5.40 , 4.29 , 1.83
Height h (cm): 10.3 , 11.2 , 19.8 , 35.2 , 3.81
Question: Determine a quantity that, when you plot h against it, should yield a straight line.
A. 4mg/x
B. x^2/2mg
C. x/mg
D. mg/square root of (2x)
What is the answer?
FrictionlessExplanation / Answer
The quantity when we plot h against to it,should be yield a straight line
Consider the quantity as z ,for straight line z and h in the form of
z= ch -----------------------(1)
Here c is constant and it gives the slope of the straight line
Now come to our problem
From the law of conservation of energy
The energy stored in a spring due to compression x= potential energy of the block at a vertical hight h
(1/2) k x2 =m g h --------------(2)
Here k is the spring of force constant and it is constant value
x is the compression in the spring
m is the mass of the block
h vertical height
From (2) we can write
kx2/(2mg)=h
x2/(2mg)=(1/k) h -----------(3)
When we compare above equation (3) with (1) it is clear that it is in the form of straight line
z=(x2/2mg) , c= (1/k)
Therefore the required quantity is x2/2mg
so option B is correct.