Answer:
A. a rigorously tested explanation
Explanation:
- B. and D. are out - theories are not opinionated, they are factual
- C. is out - not all theories are mathematical
- A. is the best choice
'Density' is defined as (mass) / (volume). You need enough information to be able to measure or calculate the mass and the volume of the object.
I think its b too but i may be wrong
Answer:
Option 5. 1 and 3
Solution:
The only forces acting on the tennis ball after it has left contact with the racquet and the instant before it touches the ground are the force of gravity in the downward direction and the force by the air exerted on the ball.
The ball after it left follows the path of trajectory and as it moves forward in the horizontal direction the force of the air acts on it.
In the whole projectile motion of the ball, the acceleration due to gravity acts on the ball thus the force of gravity acts on the ball in the downward direction before it hits the ground.
Answer:
The work done by the steam is 213 kJ.
Explanation:
Given that,
Mass = 5 kg
Pressure = 150 kPa
Temperature = 200°C
We need to calculate the specific volume
Using formula of work done
Where,R = gas constant
T = temperature
P = pressure
=Atmosphere pressure
m = mass
Put the value into the formula
Hence, The work done by the steam is 213 kJ.
