A ball is thrown vertically upwards with a speed of 20 m/s. How high will it ris
Practice Questions
Q1
A ball is thrown vertically upwards with a speed of 20 m/s. How high will it rise before coming to rest momentarily? (g = 10 m/s²)
20 m
40 m
10 m
30 m
Questions & Step-by-Step Solutions
A ball is thrown vertically upwards with a speed of 20 m/s. How high will it rise before coming to rest momentarily? (g = 10 m/s²)
Correct Answer: 20 m
Step 1: Identify the initial speed (u) of the ball, which is 20 m/s.
Step 2: Recognize that the final speed (v) at the highest point is 0 m/s because the ball comes to rest momentarily.
Step 3: Note that the acceleration (a) due to gravity is -10 m/s² (negative because it acts downwards).
Step 4: Use the formula v² = u² + 2as to find the height (h).
Step 5: Substitute the values into the formula: 0 = (20)² + 2(-10)h.
Step 6: Simplify the equation: 0 = 400 - 20h.
Step 7: Rearrange the equation to solve for h: 20h = 400.
Step 8: Divide both sides by 20 to find h: h = 400 / 20.
Step 9: Calculate the height: h = 20 m.
Kinematics – The study of motion, particularly the equations that describe the relationship between velocity, acceleration, and displacement.
Equations of Motion – Using the kinematic equation v² = u² + 2as to solve for displacement when initial velocity, final velocity, and acceleration are known.