Final answer:
A drum can become convex shaped due to increased pressure inside the drum when it is struck. The impact from the drumstick creates sound waves that cause the air inside the drum to vibrate and exert pressure on the drum's surface, pushing it outward.
Step-by-step explanation:
A drum can become convex shaped due to an increase in pressure inside the drum. When a drum is struck, the impact creates sound waves that travel through the air inside the drum, causing the air to vibrate. As the air vibrates, it exerts pressure on the drum's surface, pushing it outward and causing it to become convex in shape.
For example, when you hit a drum with a drumstick, the impact creates a sound wave that travels through the air inside the drum. This sound wave causes the air to vibrate, and the vibrations exert pressure on the drum's surface, pushing it outwards and causing it to bulge.