Answer:
The time taken for the race is 17.20 s.
Explanation:
It is given in the problem that a 62.0 kg sprinter starts a race with an acceleration of 1.44 meter per second square.The initial speed of the sprinter is zero as it starts from the rest.
Calculate the final speed of the sprinter.
The expression for the equation of the motion is as follows;
Here, u is the initial speed, v is the final speed, a is the acceleration and s is the distance.
Put u= 0, s=30 m and 
.
Calculate time taken to cover 30 m distance.
The expression for the equation of motion is as follows;
Put u= 0, s=30 m and .
t=6.45 s
Calculate the time taken to complete his race.
T= t+t'
Here, t is the time taken to cover 30 m distance and t' is the time taken to cover 100 m distance.
Put s= 30 m, and s'= 100 m.
T= 17.20 s
Therefore, the time taken for the race is 17.20 s.
I hope it is clearly visible.. Velocity of the center of mass of 2-ball system is - 11.54m/s. Minus indicates, velocity direction is in downward direction.
Well we know the correct answer cannot be "a" bcause velocity is tangent to the circlular path of an object experienting centripical motion. Velocity DOES NOT point inward in centripical motion.
we know the correct answer cannot be "b" because "t" stands for "time" which cannot point in any direction. so, time cannot point toward the center of a circle and therefore this answer must be incorrect.
I would choose answer choice "c" because both force and centripical acceleration point toward the center of the circle.
I do not think answer choice "d" can be correct because the velocity of the mass moves tangent to the circle. velocity = (change in position) / time. Therefore, by definition the mass is moving in the direction of the velocity which does not point to the center of the circle.
does this make sense? any questions?
Answer:
I believe the answer is A and D.
I am unsure of C.
Answer:
Water is a polar molecule
Explanation:
The general solubility rule is that like dissolves like. In short, polar solutes would dissolve in polar solvents. Non polar solutes also dissolves on non polar solvents.
NaCl is an ionic molecule which forms as a result of transfer of electrons from one atom to another. The transfer of electrons makes the atoms oppositely a charged ions and they become polar.
Water is made up of Hydrogen H⁺ ions and hydroxy ions OH⁻. Water is an heteronuclear covalent molecule. Here, there is an unequal sharing of electrons as one atom pulls the shared electron more closer. This leaves a partial negative charge on the more electronegative atom and a partial positive charge on the other.
This polar nature of water NaCl makes dissolution easy.
