Problem Solving

[abhilashmur]

I need help with this accelaration question. After doing 7 out of 10 problem solving, my brain is not working.

Please someone help me.

. A rock is thrown upward with an initial velocity, v(t) of 18m/s from a height , h(t), of 45m. If the acceleration of the rock is a constant -9 m/s^2, find the height of the rock at time t=4


Thanks

 

[tkhunny]

I would be VERY interested in knowing anything about the first 7 problems. Give an example of one you could solve.

 

[Deleted member 4993]

I need help with this accelaration question. After doing 7 out of 10 problem solving, my brain is not working.

Please someone help me.

. A rock is thrown upward with an initial velocity, v(t) of 18m/s from a height , h(t), of 45m. If the acceleration of the rock is a constant -9 m/s^2, find the height of the rock at time t=4


Thanks

\(\displaystyle h(t) \ = h_o + v_o * t + 0.5 * a * t^2\)

Surely, you know this "famous" formula (sometimes called Galileo's second equation) - even without defining the variables......

 

[TchrWill]

I need help with this accelaration question. After doing 7 out of 10 problem solving, my brain is not working.

Please someone help me.

. A rock is thrown upward with an initial velocity, v(t) of 18m/s from a height , h(t), of 45m. If the acceleration of the rock is a constant -9 m/s^2, find the height of the rock at time t=4

For a body launched upward
h(t) = h + Vo(t) - g(t^2)/2

h(t) = height reached after time "t"
h = initial height = 45m
Vo = initial velocity = 18m/s
g = acceleration due to gravity = 9.8m/s^2

Therefore, h(4) = 45 + 18(4) - 9.8(4^2)/2

 

[abhilashmur]

Thank You to Subhotosh Khan & TchrWill for helping me.

This is especially for tkhunny : So, you want an example. You got it

A radioactive element decays exponentially proportionally to its mass. One half of its original amount remains after 5750 years. If 10000 grams of the element are present initially, how much will be left after 1000 years?

M=Mi( 1/2) (t/5750)
t= 1000 years
Mi = 10000
M = 10000 (1/2) ( 1000/5750)( cross the zero out)
M= 8864 grams


Example 2

A trough is 14 ft long and its ends have the shape of isosceles triangles that are 2 ft across at the top and have a height of 1 ft. If the trough is being filled with water at a rate of 8 ft3/min, how fast is the water level rising when the water is 9 inches deep?


l V=(1/2)(x)(2x).14=14x^2 dV/dx=28x
(dV/dt).(dt/dx)=28x dt/dx=28x.
( dt/dx=28(9/12).1/8
dx/dt=24/63. So the water level increases at the rate of 24/63 ft /min


Hope this finds you I do my homework always. I thought this message board is to help students who wanted to learn and need help not for teasing a student. I never plan to post any of my doubt again. Such a insult to me by one person. Sorry to say this.

Thank you for the wonderful support given by you.

Abhilash

 

[tkhunny]

I dare you to show teasing or doubt. I have not edited. It is not unreasonable to assess a student's current knowledge.

In the future, just answer the questions you are presented and we will all get along just fine.