Answer:
option b ) is correct
Explanation:
Let d be the distance in km from the place of lightning . velocity of sound is 340 m /s approx
in km/ s it is 0.34 km/s
time in sec taken by sound to cover a distance of d km
d / .34 = t
d = .34 t
d =
d = t / 3
so option b ) is correct . ,
Answer:
G = 6.6675 x N/
Explanation:
From Newton's law of universal gravitation,
F = .................. 1
Where F is the force of attraction, G is the universal gravitation constant, M is the mass of a massive object e.g earth, m is the mass of the smaller object e.g moon, r is the radius of the massive object.
Newton's second law states;
F = mg ................... 2
F is the force, m is the mass of the object and g is the gravitational force on the object.
Equating equations 1 and 2 gives;
mg =
So that;
g =
⇒ G =
where: g = 9.81 m/, r = 6371 km, M = 5.972 x kg.
G =
=
= 6.6675 x N/
The Universal Gravitational Constant (G) is 6.6675 x N/.
Answer: Snakes are reptiles
Explanation: All reptiles are ectothermic (they obtain body heat from their environment).
Momentum, p = m.v
m of the girl = 60.0 kg
m of the boat = 180 kg
v of the girl = 4.0 m/s
A) Momentum of the girl as she is diving:
p = m.v = 60.0 kg * 4.0 m/s = 24.0 N/s
B) momentum of the raft = - momentum of the girl = -24.0 N/s
C) speed of the raft
p = m.v ; v = p/m = 24.0N/s / 180 kg = -0.13 m/s [i.e. in the opposite direction of the girl's velocity]