# Physics

posted by .

An object is thrown vertically and has an upward velocity of 5 m/s when it reaches three fourths of its maximum height above its launch point. What is the initial (launch) speed of the object?

• Physics -

total energy at beginning=totalenergy at point above
1/2 m vi^2=1/2 m 5^2+mg(3/4 h)

this indicates that you have two variables, height, and velocity initially.

but we know in the final 1/4 h, vf=0, and

Vf^2=Vi^2+2gd
0=25-2*9.8*h/4
or h=50/9.8
now you can solve for vi in the first equation.

## Similar Questions

1. ### Physics

An object is thrown vertically and has an upward velocity of 18 m/s when it reaches one fourth of its maximum height above its launch point. What is the initial (launch) speed of the object?
2. ### physics

In the absence of air resistance two balls are thrown upward from the same launch point. Ball A rises to a maximum height above the launch point that is four times greater than that of ball B. The launch speed of ball A is _______ …
3. ### Physics

An object is thrown vertically and has an upward velocity of 5 m/s when it reaches three fourths of its maximum height above its launch point. What is the initial (launch) speed of the object?
4. ### physics

An object is thrown vertically upward such that it has a speed of 56 m/s when it reaches two thirds of its maximum height above the launch point. Find the maximum height h. The acceleration of gravity is 9.8 m/s 2 . Answer in units …
5. ### Physics

An object is thrown vertically upward such that it has a speed of 32 m/s when it reaches two thirds of its maximum height above the launch point. Find the maximum height h. The accelera- tion of gravity is 9.8 m/s2 . Answer in units …
6. ### Physics

A ball is thrown straight upward and rises to a maximum height of 20 m above its launch point. At what height above its launch point has the speed of the ball decreased to one-half of its initial value?
7. ### Physics

An object is thrown vertically upward and has a speed of 12 m/s when it reaches one fifth of its maximum height above the launch point. Determine its maximum height. g=9.81 m/s^2. Please help
8. ### Physics

An object is thrown vertically upward and has a speed of 12 m/s when it reaches one fifth of its maximum height above the launch point. Determine its maximum height. g=9.81 m/s^2. Please help
9. ### physics

An object is thrown vertically up and attains an upward velocity of 10 m/s when it reaches one fourth of its maximum height above its launch point. What was the initial speed of the object?
10. ### PAKISTAN

Q23. Object is thrown vertically upwards and has a speed of 18 m/s when it reaches one-fourth of its maximum height h above its launch point. Label the relevant points and answer the following; a) Determine the maximum height h. b) …

More Similar Questions