A stone is dropped from a height of 20 m. How long does it take to reach the ground?
Practice Questions
1 question
Q1
A stone is dropped from a height of 20 m. How long does it take to reach the ground?
2 s
1 s
3 s
4 s
Using h = (1/2)gt², where h = 20 m and g = 9.8 m/s², we have 20 = (1/2)*9.8*t². Solving gives t² = 4.08, so t ≈ 2 s.
Questions & Step-by-step Solutions
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Q
Q: A stone is dropped from a height of 20 m. How long does it take to reach the ground?
Solution: Using h = (1/2)gt², where h = 20 m and g = 9.8 m/s², we have 20 = (1/2)*9.8*t². Solving gives t² = 4.08, so t ≈ 2 s.
Steps: 7
Step 1: Identify the height from which the stone is dropped. In this case, the height (h) is 20 meters.
Step 2: Understand that the formula to calculate the time (t) it takes for an object to fall from a height is h = (1/2)gt², where g is the acceleration due to gravity (approximately 9.8 m/s²).
Step 3: Substitute the known values into the formula. We have h = 20 m and g = 9.8 m/s², so the equation becomes 20 = (1/2) * 9.8 * t².
Step 4: Simplify the equation. First, calculate (1/2) * 9.8, which equals 4.9. Now the equation is 20 = 4.9 * t².
Step 5: To isolate t², divide both sides of the equation by 4.9. This gives t² = 20 / 4.9.
Step 6: Calculate 20 / 4.9, which is approximately 4.08. So now we have t² = 4.08.
Step 7: To find t, take the square root of 4.08. This gives t ≈ 2 seconds.
