In 1842, Julius Robert Mayer discovered The law of conservation of Energy. It its most compact form, it it now called The first law of Thermodynamics
Energy can neither be created nor destroyed, it can only be changed to another form of energy.
Answer:
Option D (Alphonse Bertillon) is the correct response.
Explanation:
- He seems to have been a policeman turned biometrics expert from France. Forensic techniques such as forensic record analysis were developed by Bertillon.
- To retain proof, he always pioneered or developed the use of such galvanoplastic compounds as molds for footsteps as well as ballistics. To research physical changes with age, Bertillon has developed a method focused on images of almost the same person’s performance.
All those other choices weren’t connected to the instance offered. So, the best one is the one described.
Answer:
20.42 N/m
Explanation:
From hook's law,
F = ke ......................... Equation 1
Where F = Force applied to the spring., k = spring constant, e = extension.
Make k the subject of the equation,
k = F/e ................. Equation 2
Note: The force on the spring is equal to the weight of the mass hung on it.
F = W = mg.
k = mg/e................ Equation 3
Given: m = 250 g = 0.25 kg, e = 37-25 = 12 cm = 0.12 m.
Constant: g = 9.8 m/s²
Substitute into equation 3
k = (0.25×9.8)/0.12
k = 20.42 N/m.
Hence the spring constant = 20.42 N/m
Following your push the ball rolls down the lane at 4.2m/s. What is the net force on the ball as it rolls down the lane at the constant speed?
Explanation:
It is given that,
Mass of the object, m = 0.8 g = 0.0008 kg
Electric field, E = 534 N/C
Distance, s = 12 m
Time, t = 1.2 s
We need to find the acceleration of the object. It can be solved as :
m a = q E.......(1)
m = mass of electron
a = acceleration
q = charge on electron
"a" can be calculated using second equation of motion as :
a = 16.67 m/s²
Now put the value of a in equation (1) as :
q = 0.0000249 C
or
Hence, this is the required solution.
