1) We can solve this part of the problem by using the law of conservation of energy. In fact, the initial energy of the ball is just kinetic energy:
where m is the mass of the ball and v is the initial speed of the ball. At its maximum height, the speed of the ball is zero, so its energy is just gravitational potential energy:
where g is the gravitational acceleration and h is the height above the ground.
Since the total energy must be conserved, we have
which means
If we use h=45 m, we find the minimum speed v such that the ball reaches an altitude of 45 m above the ground:
2) The motion of the ball is an accelerated motion, and the relationship between the distance covered by the ball and the time t is given by
where t is the time the ball takes to reach the altitude h=45 m. Rearranging the equation, we find
Momentum = mass X Velocity
Using logic we can see that the velocity would be positive so 2.40 doesn't change.
120/2.40 = 50kg
Mass of object is 50 kg.
Hope that helps! :)
Answer:
0.1014 J
Explanation:
Considering the air resistance negligible kinetic energy is given by
K.E = (1/2) m v^2
K.E = 0.5 x 0.12 x (1.3)^2
K.E = 0.06 x 1.69
K.E = 0.1014 J
Taking into account the definition of calorimetry and sensible heat, the amount of energy required is 68.8 J.
<h3>Calorimetry</h3>
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
<h3>Sensible heat</h3>
Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).
In this way, between heat and temperature there is a direct proportional relationship. The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat by the mass of the body.
So, the equation that allows to calculate heat exchanges is:
Q = c× m× ΔT
where:
- Q is the heat exchanged by a body of mass m.
- c is the specific heat substance.
- ΔT is the temperature variation.
<h3>Energy required in this case</h3>
In this case, you know:
- Q= ?
- c= 0.215
- m= 20 g
- ΔT= Tfinal - Tinitial= 88 C - 72 C= 16 C
Replacing in the definition of sensible heat:
Q = 0.215 × 20 g× 16 C
Solving:
<u><em>Q=68.8 J</em></u>
Finally, the amount of energy required is 68.8 J.
Learn more about calorimetry:
<u>brainly.com/question/11586486?referrer=searchResults</u>
<u>brainly.com/question/24724338?referrer=searchResults</u>