Becky has a younger sister. If the sister was half Becky's age when Becky was 6, and Becky is now 70, how old is Becky's sister?
2 answers:
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Answer:
Explanation:
<u>Conservation of Momentum </u>
The total momentum of a system of two particles is
Where m1,m2,v1, and v2 are the respective masses and velocities of the particles at a given time. Then, the two particles collide and change their velocities to v1' and v2'. The final momentum is now
The momentum is conserved if no external forces are acting on the system, thus
Let's put some numbers in the problem and say
120=120
It means that when the particles collide, the first mass returns at 6 m/s and the second continues in the same direction at 28 m/s
Answer:
The equivalent stiffness of the string is 8.93 N/m.
Explanation:
Given that,
Spring stiffness is
According to figure,
and
is in series
We need to calculate the equivalent
Using formula for series
Put the value into the formula
k and is in parallel
We need to calculate the k'
Using formula for parallel
Put the value into the formula
,k' and
is in series
We need to calculate the equivalent stiffness of the spring
Using formula for series
Put the value into the formula
Hence, The equivalent stiffness of the string is 8.93 N/m.
