Answer:
a = 0.7267
, acceleration is positive therefore the speed is increasing
Explanation:
The definition of acceleration is
a = dv / dt
they give us the function of speed
v = - (t-1) sin (t² / 2)
a = - sin (t²/2) - (t-1) cos (t²/2) 2t / 2
a = - sin (t²/2) - t (t-1) cos (t²/2)
the acceleration for t = 4 s
a = - sin (4²/2) - 4 (4-1) cos (4²/2)
a = -sin 8 - 12 cos 8
remember that the angles are in radians
a = 0.7267
the problem does not indicate the units, but to be correct they must be m/s²
We see that the acceleration is positive therefore the speed is increasing
Answer:
The Mass of a person is calculated to be 28.6kg .
Explanation:
This is based on Kinetic energy and we know, that Kinetic energy is the energy possessed by body by virtue of its motion .
It can be calculated by expression :
K.E=1/2mv²
Velocity of a person = 11.2m/sec
Kinetic energy = 1800J
Mass of person = ?
We know ,
K.E=1/2mv²
so, putting values we have :
1800=1/2 x m x (11.2)²
That is ,
m=1800 x 2 /11.2 x 11.2
or
m=3600/125.44
m = 28.6 kg
It is possible because the rubber ball has mechanical energy which is equal to potential energy.
<h3>
What is mechanical energy?</h3>
Mechanical energy of an object is the total energy possessed by the object, including the potential energy and the kinetic energy.
M.A = K.E + P.E
<h3>What is kinetic energy?</h3>
Kinetic energy is the energy possessed by an object due to its motion.
<h3>What is potential energy?</h3>
Potential energy is the energy possessed by an object due to its position.
When kinetic energy (K.E) = 0
M.A = P.E
Thus, it is possible because the rubber ball has mechanical energy which is equal to potential energy.
Learn more about mechanical energy here: brainly.com/question/24443465
