Answer:
Explanation:
Speed of an object is defined as the ratio of the distance covered by the object to the time taken to cover that distance.
Let
be the speed of the object.
Let
be the distance travelled by the object.
Let
be the time taken by the object.
So,
s=
So,the speed of the car is 
Answer:
T = 4.905[N]
Explanation:
In order to solve this problem we must perform a sum of forces on the vertical axis.
∑Fy = 0
We have two forces acting only, the weight of the body down and the tension force T up, as the body does not move we can say that it is system is in static equilibrium, therefore the sum of forces is equal to zero.
![T-m*g=0\\T=0.5*9.81\\T=4.905[N]](https://tex.z-dn.net/?f=T-m%2Ag%3D0%5C%5CT%3D0.5%2A9.81%5C%5CT%3D4.905%5BN%5D)
At stp (standard temperature and pressure), the temperature is T=0 C=273 K and the pressure is p=1.00 atm. So we can use the ideal gas law to find the number of moles of helium:

where p is the pressure (1.00 atm), V the volume (20.0 L), n the number of moles, T the temperature (273 K) and

the gas constant. Using the numbers and re-arranging the formula, we can calculate n: