Answer:
Second projectile is 1.4 times faster than first projectile.
Explanation:
By linear momentum conservation
Pi = Pf
m x U + M x 0 = (m + M) x V

Now Since this projectile + pendulum system rises to height 'h', So using energy conservation:
KEi + PEi = KEf + PEf
PEi = 0, at reference point
KEf = 0, Speed of system zero at height 'h'

PEf = (m + M) g h
So,


So from above value of V
Initial velocity of projectile =U

Now Since mass of projectile and pendulum are constant, So Initial velocity of projectile is proportional to the square root of height swung by pendulum.
Which means



U₂ = 1.41 U₁
Therefore we can say that ,Second projectile is 1.4 times faster than first projectile.
<span>a = (v2 - v1)/t= acceleration formula
a = (70 - 0)/7
a = 10 km/hr/sec
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It's better to use as few units as possible.
10 km/hr = 10 km*1000 m/km/(1 hr*3600 sec/hr) = 25/9 m/sec
a= 25/9 m/sec/se</span>
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Answer:
The student hears the wave that is transmitted by the desk
Explanation:
Mechanical waves need a material medium to be able to be transmitted, in the case of sound waves, one of the most common media is air, but it is also transmitted in other media in this case, stationery is transmitted.
The student hears the wave that is transmitted by the desk
The speed of the wave is proportional to the density of the material, so the wave that the student hears arrives much faster through the desk than through the air