Answer:
a) a = 1 [m/s²]
b) a = 0.25 [m/s²]
Explanation:
To solve this problem we must use the following equation of kinematics.
a)
Between 0 and 2 seconds
where:
Vf = final velocity = 2 [m/s]
Vo = initial velocity = 0
a = acceleration [m/s²]
t = time = 2 [s]
Note: the positive sign of acceleration in the previous equation allows us to appreciate that the velocity is increasing
2 = 0 + a*2
a = 2/2
a = 1 [m/s²]
b)
Between 2 and 4 seconds
where:
Vf = final velocity = 2.5 [m/s]
Vo = initial velocity = 2
a = acceleration [m/s²]
t = time = (4 - 2) = 2 [s]
2.5 = 2 + a*2
2.5 - 2 = 2*a
0.5 = 2*a
a = 0.25 [m/s²]
Answer:
Because radiation does not require material medium for its propagation.
Explanation:
Radiation is one of the types of modes of heat transfer that takes place majorly in gases. Heat energy can be transferred through gases by radiation without heating up the intervening medium. Even, if the available molecules of gases are evacuated, the heat energy would propagate.
Thus, student's hands were not heated by convection since convection is a mode where material medium is required for propagation of heat energy.
Answer: Light passes through the front of the eye (cornea) to the lens. The cornea and the lens help to focus the light rays onto the back of the eye (retina). The cells in the retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve and then to the brain.
Explanation:
When light rays reflect off an object and enter the eyes through the cornea (the transparent outer covering of the eye), you can then see that object. The cornea bends, or refracts, the rays that pass through the round hole of the pupil.
The formular for determinatio of mass number is this:
Mass number = number of proton + number of neutron
From the question, we are told that:
Mass number = 39
Proton number = 19
Number of proton = ?
Number of neutron = mass number - number of proton
Number of neutron= 39 - 19 = 20
Therefore, number of neurtron = 20.