Answer:
The height in which the book is dropped from is 1.28 m.
Explanation:
Mass of the book, m = 1.5 kg
initial velocity of the book, u = 0
final velocity of the bok, v = 5 m/s
The height in which the book is dropped from is given by;
v² = u² + 2gh
v² = 0 + 2gh
v² = 2gh
h = v² / 2g
h = (5)² / (2 x 9.8)
h = 1.28 m
Therefore, the height in which the book is dropped from is 1.28 m.
Answer:
d = 63 m
Explanation:
Speed of Alex is 45 m/min.
We need to find distance he swim in 1 in 24 sec
45 m/min =0.75 m/s
Time, 1 min 24 sec = 84 sec
Speed = distance/time
Distance, d = v × t
d = 0.75 m/s × 84 s
d = 63 m
So, he will cover a distance of 63 m.
Answer:
Explanation:
Friction literally helps us in ways we can't even think of. Without it I wouldn’t be able to hold my phone as easily as I am doing… Now coming to few other things that would have been impossible without friction are :
Sneezing and still staying in the same place.
Belt-pulley drive
Ease in normal walking
Holding a bottle for drinking water
I would say B , not sure if its correct
Answer:
how fast it is moving in m/s? 0.65 m/s.
Explanation:
given information:
the length of the arm, L - 0.9 m
angle, θ = 20°
First we calculate the distance in horizontal motion
s = 2 L sin θ
= 2 (0.9) sin 20°
= 0.62 m
now calculate the time
t/2 = 2π√(L/g)
t = π√(0.9/9.8)
= 0.95 s
the speed is
v = s/t
= 0.62/0.95
= 0.65 m/s