C. increased stirring i think
Answer:
Probably competition with television news-
by 1953 television was becoming common in many houses and people could obtain news from television newscasts
Their common speed is 1.53 m/s.
<h3>What is speed?</h3>
Speed can be defined as the ratio of the distance to the time of a body in motion.
To calculate their final speed, we use the formula below.
Formula:
- mu+m'u' = V(m+m')............. Equation 1
Where:
- m = mass of the Lee
- m' = mass of Mat
- u = initial speed of Lee
- u' = initial speed of Mat
- V = Their common speed.
make V the subject of the equation
- V = (mu+m'u')/(m+m')........... Equation 2
From the question,
Given:
- m = 40 kg
- m' = 80 kg
- u = 4.6 m/s
- u' = 0 m/s
Substitute these values into equation 2
- V = [(40×4.6)+(80×0)]/(40+80)
- V = 184/120
- V = 1.53 m/s.
Hence, Their common speed is 1.53 m/s.
Learn more about speed here: brainly.com/question/3004254
According to the law of conservation of momentum, the <u> TOTAL </u> amount of momentum of a group of objects does not change unless outside _____<u>FORCES</u>____ act on the objects.
mass of the ball m = 0.63 kg
initial height h = 1.8 m
final height h ' = 3.03 m
initial speed v = 7.09 m / s
final speed v ' = 4.21 m / s
Let the work done on the ball by air resistance W = ?
we know from law of conservation of energy ,
total energy at height h + work done by air = total energy at height h '
mgh + ( 1/ 2) mv^ 2 + W = mgh ' + ( 1/ 2) mv'^ 2
0.630*9.8*1.8 + 0.63*7.09^2 + W = mgh ' + ( 1/ 2) mv'^ 2
From there you can find W
if there is negative sign indicates it work opposite direction to motion
