Answer:
a) 72.25sec
b) 6.25secs
c) after 10.5secs and 2 secs
Step-by-step explanation:
Given the height reached by the rocket expressed as;
s(t)= -4t^2 + 50t - 84
At maximum height, the velocity of the rocket is zero i.e ds/dt = 0
ds/dt = -8t + 50
0 = -8t + 50
8t = 50
t = 50/8
t = 6.25secs
Hence it will reach the maximum height after 6.25secs
To get the maximum height, you will substitute t - 6.25s into the given expression
s(t)= -4t^2 + 50t - 84
s(6.25) = -4(6.25)^2 + 50(6.25) - 84
s(6.25) = -156.25 + 312.5 - 84
s(6.25) = 72.25feet
Hence the maximum height reached by the rocket is 72.25feet
The rocket will reach the ground when s(t) = 0
Substitute into the expression
s(t)= -4t^2 + 50t - 84
0 = -4t^2 + 50t - 84
4t^2 - 50t + 84 = 0
2t^2 - 25t + 42 = 0
2t^2 - 4t - 21t + 42 = 0
2t(t-2)-21(t-2) = 0
(2t - 21) (t - 2) = 0
2t - 21 = 0 and t - 2 = 0
2t = 21 and t = 2
t = 10.5 and 2
Hence the time the rocket will reach the ground are after 10.5secs and 2 secs
What is angle A’s equation
Answer:
Step-by-step explanation:
I hope these are people in vehicles travelling toward each other.
80 mh * t + 40 mph * t = 420 miles
The two vehicles are going to travel a total of 420 miles. B will cover a lot more ground than A, but together they will make 420 miles
80t + 40t = 420
120t = 420
t = 420/120
t = 3.5
So after driving 3.5 hours, the two cars will meet.
ANSWER
45.6cm to the nearest tenth.
EXPLANATION
The diagonal of the rectangular painting is 62cm.
The height of the painting is 42 cm.
The height of the painting h , the diagonal, and the width of the painting forms a right triangle with the diagonal being the hypotenuse.
From the Pythagoras Theorem,
The width of the painting is 45.6cm to the nearest tenth.
