# Math Help - Physics (test tomorrow) word problems: Two-dimensions/gravitation

1. ## Physics (test tomorrow) word problems: Two-dimensions/gravitation

Really anxious. Thanks in advance to those who helped.

1. A rock is tied to a string and spun in a horizontal circle. The string is 1.8m long and the rock has an acceleration of 3.4m/s^2. What is the tangential velocity of the rock?

2. A marble rolls off the edge of a table that is 0.734m high. The marble is moving at a speed of 0.122m/s at the moment that it leaves the edge of the table. How far from the table does the marble land?

3. A 0.45kg ball is attached to the end of a cord of length 1.4meters. The ball is whirled in a circular path om a horizontal plane. The cord can withstand a maximum tension of 57.0 Newtons before it breaks. What is the maximum speed the ball can have without breaking?

Thanks again.

2. Originally Posted by trancefanatic
Really anxious. Thanks in advance to those who helped.

1. A rock is tied to a string and spun in a horizontal circle. The string is 1.8m long and the rock has an acceleration of 3.4m/s^2. What is the tangential velocity of the rock?

2. A marble rolls off the edge of a table that is 0.734m high. The marble is moving at a speed of 0.122m/s at the moment that it leaves the edge of the table. How far from the table does the marble land?

3. A 0.45kg ball is attached to the end of a cord of length 1.4meters. The ball is whirled in a circular path om a horizontal plane. The cord can withstand a maximum tension of 57.0 Newtons before it breaks. What is the maximum speed the ball can have without breaking?

Thanks again.
1. Use $a = \frac{v^2}{r}$.

2. Basic projectile motion problem.

Consider motion in the vertical direction to get t, the time it takes to land (u = 0, y = 0.734 m, a = g = 9.8 m/s^2, t = ?).

Consider motion in the horizontal direction to get x, the distance from the table (u = 0.122 m/s, a = 0, t = see above, x = ?).

3. $T = \frac{m v^2}{r}$. Set T = 57 N.