Answer: Water on Earth was transported here by comets. The correct option is A.
Explanation:
Comets are made up of water with ice, rock and minerals.
Alot of research and hypotheses has been made to prove the origin of water on planet earth. Extraplanetary source such as comets, trans-Neptunian objects, and water-rich meteoroids (protoplanets) are believed to have delivered water to Earth.
Answer : The half-life of this substance will be, 45 minutes.
Explanation :
First we have to calculate the value of rate constant.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant = ?
t = time passed by the sample = 90.3 min
a = initial amount of the reactant = 400
a - x = amount left after decay process = 100
Now put all the given values in above equation, we get
Now we have to calculate the half-life of substance, we use the formula :
Therefore, the half-life of this substance will be, 45 minutes.
Answer:
0.114
Explanation:
There are two forces acting on the cart in the direction along the cart:
- The component of the gravitational force in the direction parallel to the ramp, , down along the ramp
- The force of friction, , up along the ramp
So the equation of motion along this direction is:
(1)
where
m is the mass of the cart
is the acceleration due to gravity
is the angle of the ramp
is the coefficient of kinetic friction
N is the normal force exerted by the ramp on the cart
is the acceleration of the cart
The normal force can be found from the equation of the forces along the direction perpendicular to the ramp; in fact, the normal force is balanced by the component of the weight perpendicular to the ramp, so we have:
From which we get:
Substituting into (1),
And solving for , we find the coefficient of friction:
Answer:
2.70
Explanation:
pH = -log[H+]
pH = -log[2.0x10^-3]
pH = 2.70
Answer:
361.46 N
Explanation:
= Coefficient of thermal expansion =
Y = Young's modulus for steel =
A = Area =
= Original length = 1.28 km
= Change in temperature =
Length contraction is given by
Also,
The tension in the wire is 361.46 N
Answer:
Information from the leading mathematicians was considered "classified".