Question 19M.2.SL.TZ2.bi
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.SL.TZ2.bi |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Calculate | Question number | bi | Adapted from | N/A |
A student strikes a tennis ball that is initially at rest so that it leaves the racquet at a speed of 64 m s–1. The ball has a mass of 0.058 kg and the contact between the ball and the racquet lasts for 25 ms.
The student strikes the tennis ball at point P. The tennis ball is initially directed at an angle of 7.00° to the horizontal.
The following data are available.
Height of P = 2.80 m
Distance of student from net = 11.9 m
Height of net = 0.910 m
Initial speed of tennis ball = 64 m s-1
Calculate the time it takes the tennis ball to reach the net.
[2]
horizontal component of velocity is 64.0 × cos7° = 63.52 «ms−1» ✔
» ✔
Do not award BCA. Check working.
Do not award ECF from using 64 m s-1.
This question scored well at HL but less so at SL. One common mistake was to calculate the direct distance to the top of the net and assume that the ball travelled that distance with constant speed. At SL particularly, another was to consider the motion only when the ball is in contact with the racquet.
