Answer:
Explanation:
Given
mass of each railroad is M
first railroad is moving with velocity
and other two's with 
conserving Momentum

where v_f is the final velocity of combined system
(b)Initial Kinetic Energy


Final Kinetic Energy

Loss in Kinetic Energy


We have that for the Question, it can be said that the amount by which the length of the stack decreases is
From the question we are told
A copper (<em>Young's modulus </em>1.1 x 1011 N/m2) cylinder and a brass (Young's modulus 9.0 x 1010 N/m2) cylinder are stacked end to end, as in the drawing. Each <em>cylinder </em>has a radius of 0.24 cm.
A compressive force of F = 7900 N is applied to the right end of the brass cylinder. Find the amount by which the length of the stack <em>decreases</em>.
Generally the equation for <em>copper </em>cylinder is mathematically given as



Generally the equation for brass<em> </em>cylinder is mathematically given as


Therefore Total change in length


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<span>Both objects receive the same impulse.</span>
Healthy pregnant women should get at least 150 minutes of moderate-intensity aerobic activity, spread over a 7-day period, each week - True
<u>Explanation:</u>
Women who are healthy but moderately active must be engaged with aerobic activities moderately. they should be engaged with this activities at least 2 and a half hours in all 7 days of a week. They must be engaged with this activity during the pregnancy time and also in the period after their delivery.
During the time of pregnancy all women must be healthy and physically active. The ways for maintaining a very good health in the pregnancy time will be guided by the health care providers. Women should be highly active during and after pregnancy time. This helps in having a baby that is also very healthy.