Answer:
-7.14
Explanation:
According to equation of motion
v = u + at
where
v is the final velocity at any time t
u is the initial velocity
a is the acceleration
and t is the time
___________________________________________
Given
An object is thrown upward it means
its initial velocity is in upward direction
but acceleration due to gravity is in downward direction which will cause to decrease the velocity of object.
Intial velocity u = 31.1 m/s
final velocity v at 4 second we have to find.
t = 4 second
a = g = 9.81 m/s2 (it is acting in opposite direction of motion hence its sign will be negative ).
Thus
a = - 9.81 m/s2
using the above values in v = u + at
v = 32.1 - 9.81*4
v = 32.1 - 39.24
v = -7.14
Thus, correct option is -7.14.
Answer:
A. 40 J
Explanation:
Given;
heat added to the system, Q = 70 J
work done by the system, W = 30 J
The change in the internal energy of the system is calculated using the first law of thermodynamic as shown below;
ΔU = Q - W
ΔU = 70 J - 30 J
ΔU = 40 J
Therefore, the change in the internal energy of the system is 40J
<span>The correct answer is D. The system that is completely open of the available answers would be an open pot of boiling water. This is due to the fact that an open system is defined as one in which energy or mass can be put out into or taken from the environment. Therefore, the evaporation of water due to the heat when a pot is boiling would be an example of lost energy, and therefore this is an open system.</span>
Answer:
602.27 kg
Explanation:
The computation of the largest mass of cargo the balloon can lift is shown below:-
Volume of helium inside the ballon= (4 ÷ 3) × π × r^3
= (4 ÷ 3) × 3.14 × 6.953
= 1406.19 m3
Mass the balloon can carry = volume × (density of air-density of helium)
= 1406.19 × (1.29-0.179)
= 1562.27 kg
Mass of cargo it can carry = Mass it can carry - Mass of structure
= 1562.27 - 960
= 602.27 kg
All you need is your science book
