The horizontal speed has no effect on the answer.
It doesn't matter whether you flick a marble horizontally from the roof,
fire a high-power rifle horizontally from the roof, drive a school bus straight
off the roof, or drop a bowling ball from the roof with zero horizontal speed.
Their vertical speed is completely determined by gravity, (and it happens to
be the same for all of them).
Handy dandy formula for the distance covered by anything that starts out
with zero speed and accelerates to the end:
Distance = (1/2) (acceleration) x (time)²
If the beginning of the journey is on Earth, then the acceleration is
9.8 m/s² ... the acceleration of gravity on Earth. We'll assume that
the 55-meter rooftop in the question is part of a building on Earth.
55 meters = (1/2) (9.8 m/s²) x (time)²
Divide each side
by 4.9 m/s² : 55 m / 4.9 m/s² = (time)²
(time)² = (55/4.9) sec²
Square-root
each side: time = √(55/4.9 sec²)
= 3.35 sec .
Answer:
A light beam incident on a diffraction grating consists of waves with two different wavelengths. The separation of the two first order lines is great if
the dispersion is great
Answer:
Second Choice.
Explanation:
Jack's Power = W/t
Jill's Power = 2W/(0.5)*t
2/0.5 = 4
Jill's Power = 4*W/t
Jill's Power is 4 times greater than Jack's
Second Choice
Answer:
option D
Explanation:
given.
horizontal velocity of arrow and a ball given as 50 m/s and 44 m/s respectively from the top of a building over flat ground.
In vertical direction, they are both identical
In vertical direction the initial velocity of arrow and a ball is 0 m/s
Their acceleration due to gravity is same for both arrow and a ball 9.8 m/s²
they will react bottom at the same time
time of flight is same for both
now,
In horizontal direction,
distance = speed × time
Since speed is more for arrow, it will travel more horizontal distance at the same time.
the correct answer is option D
