DP Physics (last assessment 2024)
Question 21M.2.SL.TZ1.2
| Date | May 2021 | Marks available | [Maximum mark: 5] | Reference code | 21M.2.SL.TZ1.2 |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Determine, Explain, State | Question number | 2 | Adapted from | N/A |
2.
[Maximum mark: 5]
21M.2.SL.TZ1.2
A planet is in a circular orbit around a star. The speed of the planet is constant.
(a.i)
Explain why a centripetal force is needed for the planet to be in a circular orbit.
[2]
Markscheme
«circular motion» involves a changing velocity ✓
«Tangential velocity» is «always» perpendicular to centripetal force/acceleration ✓
there must be a force/acceleration towards centre/star ✓
without a centripetal force the planet will move in a straight line ✓
(a.ii)
State the nature of this centripetal force.
[1]
Markscheme
gravitational force/force of gravity ✓
(b)
Determine the gravitational field of the planet.
The following data are given:
Mass of planet kg
Radius of the planet m.
[2]
Markscheme
use of ✓
6.4 «Nkg−1 or ms−2» ✓