Wednesday

September 3, 2014

September 3, 2014

Posted by **Megan** on Friday, May 25, 2012 at 2:42pm.

Can someone please explain the correct equation to use thoroughly and help me to find the correct answer?!

- Physics -
**Steve**, Friday, May 25, 2012 at 2:52pmby speed, do you mean the vector sum of the horizontal and vertical speeds?

Must be, since the horizontal speed never changes, and the initial vertical speed was 0, so double that is still 0.

**v**= 4.3**i**- 9.8t**j**

|**v**| = √(4.3^2 + (9.8t)^2) = √(96.04t^2 + 18.49)

so, double the original speed is 8.6m/s and we want to find t when

8.6 = √(96.04t^2 + 18.49)

t = 0.76 sec

- Physics -
**Elena**, Friday, May 25, 2012 at 2:54pmThis is the projectile thrown with horizontal velocity.

So

v(x) = const,

v(y) = g•t.

v ² = v(x)² +v(y)²

v =2•v(x),

[2v(v)]² = v(x)² +v(y)²,

3•v(x)² =v(y)² = (g•t)²,

t =v(x) •√3/g =4.3•1.73/9.8 =0.76 s.

**Answer this Question**

**Related Questions**

physics - Sam tosses a ball horizontally off a footbridge at 4.8 m/s. How much ...

physics - Sam tosses a ball horizontally off a footbridge at 3.1 m/s. How much ...

physics - Sam tosses a ball horizontally off a footbridge at 3.2 m/s. How much ...

physics - i posted this question before however i did not understand drwls ...

physics - umm i need help...which equation would i use to solve the probnlem ...

physics - A boy reaches out of a window and tosses a ball straight up with a ...

Physics - At the beginning of a basketball game, a referee tosses the ball ...

Physics - An eagle is flying horizontally at 7.9 m/s with a fish in its claws. ...

physics - An eagle is flying horizontally at 6.8 m/s with a fish in its claws. ...

physics - An eagle is flying horizontally at 5.8 m/s with a fish in its claws. ...