A ball is dropped from a height of 80 m. How long will it take to reach the ground? (Take g = 10 m/s²) (2021)
Practice Questions
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Q1
A ball is dropped from a height of 80 m. How long will it take to reach the ground? (Take g = 10 m/s²) (2021)
4 s
5 s
6 s
8 s
Using the formula h = (1/2)gt², we have 80 = (1/2)(10)t². Solving gives t² = 16, so t = 4 s.
Questions & Step-by-step Solutions
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Q
Q: A ball is dropped from a height of 80 m. How long will it take to reach the ground? (Take g = 10 m/s²) (2021)
Solution: Using the formula h = (1/2)gt², we have 80 = (1/2)(10)t². Solving gives t² = 16, so t = 4 s.
Steps: 8
Step 1: Identify the height from which the ball is dropped. In this case, the height (h) is 80 meters.
Step 2: Use the formula for the distance fallen under gravity, which is h = (1/2)gt². Here, g is the acceleration due to gravity, which is given as 10 m/s².
Step 3: Substitute the values into the formula: 80 = (1/2)(10)t².
Step 4: Simplify the equation. First, calculate (1/2)(10) which equals 5. So the equation becomes 80 = 5t².
Step 5: To isolate t², divide both sides of the equation by 5: t² = 80 / 5.
Step 6: Calculate 80 / 5, which equals 16. Now we have t² = 16.
Step 7: To find t, take the square root of both sides: t = √16.
Step 8: Calculate the square root of 16, which is 4. Therefore, t = 4 seconds.