James and Juan were at the highest point in the football stadium, dropping water balloons on people below. Many of the balloons
2 answers:
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Velocity:
Velocity is change in displacement with respect to time:
Analysing the units, meters (displacement) and seconds (time) are basic units:
Therefore the unit of velocity is m/s
Force:
Newton's second law of motion:
Kilogram (mass) is a basic unit, and accelerations unit can be found using the equation:
Analysing the units:
Therefore, the unit of force is:
Pressure:
Pressure is given by the equation:
where S is area of effect, F is force
Area for a basic rectangle (geometric shape is arbitrary for dimensional analysis) is found by multiplying two lengths:
, the unit of area
Dividing the aforementioned unit of force by the unit of area:
, the unit of pressure
Work:
Work is given by the equation:
, (dot product may be assumed as normal multiplication for the purposes of unit analysis)
Knowing displacement's (x) unit is m:
, the unit of work.
Answer:
Explanation:
The equation for this, since we are talking about weight on an elevator, is Newton's 2nd Law adjusted to fit our needs:
where the Normal Force needed to lift that elevator car is the tension. So the equation then becomes
T = ma + w where T is the tension in the cable to lift the elevator, m is the mass of the elevator (which we have to solve for), a is the acceleration of the elevator (positive since it's going up), and w is the weight of the elevator (which we have as 5500 N). Solving first for mass:
w = mg and
5500 =- m(10) so
m = 550 kg. Now we have what we need to solve for the tension:
T = 550(4.0) + 5500 and
T = 2200 + 5500 so
T = 7700 N