A rock is thrown with an initial speed of 30 m/s at an angle of 600 above the horizontal. Neglect air resistance.

Question

3. Find the velocity of the rock two seconds later after it was thrown?

4. Find the displacement of the rock two seconds later from the position it was thrown?

1. Show ALL equations, then substitution of numerical values with units.

2. If you have a string of numbers with no preceding equation, sketch, or explanation, you will receive NO CREDIT even if it leads to the correct answer.

3. Make sure all symbols used are clearly identified on your sketch. BOX each required answer. Show work in a Logical Order – Don’t jump around.

Answer 1

Initial Horizontal Velocity = Vx = V Cos theta = 30 Cos 60 = 15m/s

Vy = Initial Vertical velocity = vy + VSin theta = 30 Sin 60 = 25.98 m/s

Acceleration ax = 0 , Velocity after 2 sec = 15m/s

Acceleration ay = - 9.8 m/s2

Vertical velocity after 2 sec = 2*25.98 -9.8*4 =32.36 m/s

Velocity after 2 sec = sqrt ( 15*15 + 32.36*32.36 = 35.67 m/s

For finding displacement

R = sqrt ( X² + y² )

X = 30m

Y = 51.92 -4.9 *4 = 32.32 m

Find R