# Physics/Math

posted by .

A 1.50 kg snowball is fired from a cliff 13.5 m high with an initial velocity of 14.0 m/s, directed 41.0° above the horizontal.
(a) Using energy techniques, rather than techniques of Chapter 4, find the speed of the snowball as it reaches the ground below the cliff.
>>>>>>>>>>>>>>>>>>>>>>>>>>>
ok so I used the equation k1+u1=k2=u2
plugging in numbers i did 1/2(1.50kg)(14m/s)^2+(1.50kg)(9.8m/s^2)(13.5m)=1/2(1.50kg)(vf)^2+(1.50kg)(9.8m/s)(0).

The answer is 21 m/s.

Well for part b the question says "What is that speed if, instead, the launch angle is 41.0° below the horizontal". How do I change my equation if the angle changing to a negative is not involved in the equation used???

The downward angle changes the initial vertical velocity to downward, or a sign change. Since it is squared, it makes no difference in the final velocity.

Ah well that was dumb for sure on my part. thanks for the help!

## Similar Questions

1. ### physics

A 1.5 kg snowball is fired from a cliff 12.5m high with an inital velocity of 14 m/s directed 41 degrees above the horizontal. a) how much work is done on the snowball by the gravitaitonal force during its flight to the flat ground …
2. ### Physics/Math

A 1.50 kg snowball is fired from a cliff 12.5 m high with an initial velocity of 14.0 m/s, directed 41.0° above the horizontal. (a) Using energy techniques, rather than techniques of Chapter 4, find the speed of the snowball as it …
3. ### Physics

A 1.50 kg snowball is fired from a cliff 13.0 m high with an initial velocity of 14.0 m/s, directed 41.0° above the horizontal. (a) Using energy techniques, rather than techniques of Chapter 4, find the speed of the snowball as it …
4. ### physics

A 0.720 kg snowball is fired from a cliff 8.10 m high. The snowball's initial velocity is 14.2 m/s, directed 30.0° above the horizontal. (a) How much work is done on the snowball by the gravitational force during its flight to the …
5. ### Physics I

A stone is projected at a cliff of height h with an initial speed of 48.0 m/s directed 60.0° above the horizontal. The stone strikes at A, 5.20 s after launching. Find the height, h, of the cliff. Find the speed of the stone just …
6. ### Physics

A baseball is thrown from the roof of a 22.3 m tall building with an initial velocity of 13.1 m/s and is directed 50.9 degrees above the horizontal. A)What is the speed of the ball just before it strikes the ground?
7. ### Physics

In the figure below, a stone is projected at a cliff of height h with an initial speed of 46.0 m/s directed 60.0° above the horizontal. The stone strikes at A, 5.30 s after launching. (a) Find the height, h, of the cliff. m (b) Find …
8. ### physics

A projectile is fired at an angle of 30ᵒ above the horizontal from the top of the cliff 600 ft high. The initial speed of the projectile is 2000 ft/s. how far will the projectile move horizontally before it hits the level ground …
9. ### physics

A stone is thrown horizontally outward from the top of a bridge, the stone is released 19.6meter above the street below.the initial velocity of the stone is 5.0m/s.determine the (a)total time that the stone is in the air (b)magnitude …
10. ### physics

a projectile is fired at an angle of 27 above the horizontal from the top of a cliff 500 ft high. The initial speed of projectile is 1670 ft/s. How far will it move horizontally before hitting the level ground at the base of the cliff?

More Similar Questions