The acceleration due to gravity on Venus is about 89% of that on Earth. This means that a ball thrown upward on Venus will experience a smaller gravitational force pulling it back to the ground. As a result, the ball will travel higher and stay in the air for a longer period of time than it would on Earth.

In addition, the air on Venus is much denser than the air on Earth. This means that the ball will experience more drag as it travels through the air. The drag force will slow the ball down and cause it to return to the ground more quickly than it would on Earth.

Combining these two effects, we can conclude that a ball thrown vertically upward on Venus will return to the ground later and with a higher velocity than it would on Earth.