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vesna_86 [32]
3 years ago
12

A river flows at a velocity of 3 km/h relative to the riverbank. A boat moves downstream at a velocity of 15 km/h relative to th

e river. What is the velocity of the boat relative to the riverbank?
Physics
1 answer:
Alexus [3.1K]3 years ago
3 0
15+3=18km/hour
Think about it like this. The boat is going 15 faster than the river, and the river is going 3 faster than the bank, so the boat is going 18 faster than the river bank
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A 30 kg dog runs at a speed of 15<br> What is the dog's kinetic energy?
sattari [20]
Ke= 1/2 mv ^ 2
15x 15 = 225
225 x 30 = 6750
6750/2 = 3375 J
Ke = 3375 J
3 0
3 years ago
A thin block of soft wood with a mass of 0.072 kg rests on a horizontal frictionless surface. A bullet with a mass of 4.67 g is
Olegator [25]

Answer:

366.90149 m/s

923.821735 J

324.734 J

Initial Kinetic energy > Final kinetic energy

Explanation:

m_1 = Mass of block = 0.072 kg

m_2 = Mass of bullet = 4.67 g

u_1 = Initial Velocity of block = 0

u_2 = Initial Velocity of bullet = 629 m/s

v_1 = Final Velocity of block = 17 m/s

v_2 = Final Velocity of bullet

In this system the linear momentum is conserved

m_{1}u_{1}+m_{2}u_{2}=m_{1}v_{1}+m_{2}v_{2}\\\Rightarrow v_2=\frac{m_{1}u_{1}+m_{2}u_{2}-m_1v_1}{m_2}\\\Rightarrow v_2=\frac{0.072\times 0+4.67\times 10^{-3}\times 629-0.072\times 17}{4.67\times 10^{-3}}\\\Rightarrow v_2=366.90149\ m/s

Final Velocity of bullet is 366.90149 m/s

The initial kinetic energy

K_i=\frac{1}{2}m_2u_2^2\\\Rightarrow K_i=\frac{1}{2}4.67\times 10^{-3}\times 629^2\\\Rightarrow K_i=923.821735\ J

The final kinetic energy

K_f=\frac{1}{2}m_2v_2^2+\frac{1}{2}m_1v_1^2\\\Rightarrow K_f=\frac{1}{2}4.67\times 10^{-3}\times 366.90149^2+\frac{1}{2}0.072\times 17^2\\\Rightarrow K_f=324.734\ J

Initial Kinetic energy > Final kinetic energy

3 0
3 years ago
Two planes leave wichita at noon. one plane flies east 30 mi/h faster than the other plane, which is flying west. at what time w
scoundrel [369]
You have to take note of the individual directions of the plane. Since one is heading east, and the other is heading west, the planes are heading at opposite directions. So, it means that their distance between each other would be equal to 1,200 miles which accounts for the sum of their individual distances. The equation is as follows:

Total Distance = Distance of slower plane + Distance of faster plane
1,200 miles = st + (30+s)(t)
where
s is the speed of the slower plane and t is the time. Since both are not given, the final answer would just be in terms of s.
1,200 = t(s + 30 + s)
t = 1200/(30+2s)
t = 600/(15+s)
4 0
3 years ago
_____ you remember to put the lid back on the jar of mayonnaise​
Lilit [14]

Answer:

Did you remember to put the lid back on the jar of mayonnaise?

Explanation: Hope this helps :)

7 0
3 years ago
All of the members of a community belong to the same species tf
Anna35 [415]
That is false

I hope this helps!
3 0
3 years ago
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