Set h to 640 and solve for t:
640 = -490t^2 + 1120t
Subtract 640 from both sides:
-490t^2 + 1120t - 640 = 0
The formula to solve a quadratic equation is:
x = -b -/+ sqrtroot (b^2-4ac)/(2a) where a = -490, b = 1120 and c = -640
Solve:
x = -1120 -/+ sqrtroot (1120^2-4(-490)(-640) )/ 2(-490)
x = 8/7 = 1.1428 = 1.14
Time was 1.14 seconds
Answer:
124
Step-by-step explanation:
The frame of film is actually 50 mm high, but it looks 16 m high on the screen.
Remember that 1 m = 1,000 mm.
So everything looks (16,000)/(50) = <u>320 times</u> as big on the screen
as it is on the film. That's called the scale factor.
The penguin is 35 mm high on the film. He'll look 320 times bigger on the screen.
(320) x (35 mm) = 11,200 mm = <u>11.2 meters</u> high