Let volume of empty boat be = 100% = 1V
and mass of boat be M
In water 10%, 0.1V of the volume is submerged.
Mass, m of 1200kg increases the submerging from 10%, 0.1V to 70%, 0.7V
M leads to 0.1V boat submerging
boat submerging.
M + 1200kg leads to 0.7V boat submerging.
This is 60%, 0.6 V increase
By comparison
(M+1200kg) * 0.1V = 0.7V * M
0.1M + 120kg = 0.7M
120kg = 0.7M - 0.1M
120kg = 0.6M
M = (120/0.6)kg
M = 200kg.
The mass of the boat is 200kg.
Answer: 4.77m/s
Explanation:
According to the law of conservation of momentum which states that the sum total of momentum of bodies before collision is equal to the sum of their momentum after collision. Note that the two bodies will move at a common velocity after colliding.
Let m1 and m2 be the mass of the first and second railroad cars
u1 and u2 be the velocities of the railroad cars
v be the common velocity
Using the formula
m1u1 + m2u2 = (m1 +m2)
m1 = 1.20×10⁴kg
m2 = 1.20×10⁴kg (body of same mass)
u1 = 7.70m/s
u2 = 1.84m/s
v = ?
(1.20×10⁴×7.7) + (1.20×10⁴×1.84) = (1.20×10⁴ + 1.20× 10⁴)v
9.24×10⁴ + 2.21×10⁴ = 2.4×10⁴v
11.45×10⁴ = 2.4×10⁴v
v = 11.45×10⁴/2.4×10⁴
v = 4.77m/s
The velocity of the cars after collision will be 4.77m/s
Answer:
the answer is A. A school crossing guard raises a stop sign that weigh 10 N
B. number of oscillations in a given period of time.
