Answer:
A) The ball hits the ground 74.45 m far from the hitting position.
B) Maximum height of the ball = 18.57 m
Explanation:
There are two types of motion in this horizontal and vertical motion.
We have velocity = 27 m/s at 45° above the horizontal
Horizontal velocity = 27cos45 = 19.09 m/s
Vertical velocity = 27sin45 = 19.09 m/s
Time to reach maximum height,
v = u + at
0 = 19.09 - 9.81 t
t = 1.95 s
So total time of flight = 2 x 1.95 = 3.90 s
A) So the ball travels at 19.09 m/s for 3.90 seconds.
Horizontal distance traveled = 19.09 x 3.90 = 74.45 m
So the ball hits the ground 74.45 m far from the hitting position.
B) We have vertical displacement
S = ut + 0.5 at²
H = 19.09 x 1.95 - 0.5 x 9.81 x 1.95² = 18.57 m
Maximum height of the ball = 18.57 m
Answer:
21.21 m/s
Explanation:
Let KE₁ represent the initial kinetic energy.
Let v₁ represent the initial velocity.
Let KE₂ represent the final kinetic energy.
Let v₂ represent the final velocity.
Next, the data obtained from the question:
Initial velocity (v₁) = 15 m/s
Initial kinetic Energy (KE₁) = E
Final final energy (KE₂) = double the initial kinetic energy = 2E
Final velocity (v₂) =?
Thus, the velocity (v₂) with which the car we travel in order to double it's kinetic energy can be obtained as follow:
KE = ½mv²
NOTE: Mass (m) = constant (since we are considering the same car)
KE₁/v₁² = KE₂/v₂²
E /15² = 2E/v₂²
E/225 = 2E/v₂²
Cross multiply
E × v₂² = 225 × 2E
E × v₂² = 450E
Divide both side by E
v₂² = 450E /E
v₂² = 450
Take the square root of both side.
v₂ = √450
v₂ = 21.21 m/s
Therefore, the car will travel at 21.21 m/s in order to double it's kinetic energy.
Before Copernicus most people were thinking that the Earth is at center of universe. In 1609 Galileo observed sky through his home made telescope.
He found 4 moons orbiting Jupiter..It was a proof that bodies are orbiting other planets and not earth alone. <span>He found the crescent shape of Venus through his telescope and this could happen only if Sun is at center.</span>
