Does a convex lens always form a real image? Explain​

Need only answer if you think you know it

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.

On mars a rock falls an unknown vertical distance from a resting position and lands in a crater. if it takes the rock 2.5 seconds to fall, how high is the cliff the rock fell from? mars' surface gravity is 3.8 m/s2. a. 9.5 m b. 11.9 m c. 15.2 m d. 23.8 m