Answer:
Explanation:
2 )
power of an electric device = V² / R where V is volts and R is resistance
putting given data
power = 9²/ 5
= 16.2 J/s
energy produced in 7 minutes
= 16.2 x 7 x 60
= 6804J .
3 ) Power of an electrical device
= V² / R
= V X I where I is current
= 4.5 x .5
= 2.25 W or J/s
4 )
energy used in 3 minutes with power of 2.25 W
= 2.25 x 3 x 60
= 405 J .
7 )
power of a electrical device
= V x I
IR x I where R is resistance .
= I²R
putting given data
power = .005² x 50
= 1.25 x 10⁻³ W .
8 )
Energy used up by a 60 W bulb in 2.5 hours
= 60 x 2.5 x 60 x 60
= 5.4 x 10⁵ J .
Answer:
3 s
Explanation:
velocity=initial velocity +a*t
34=10 + 8t
24=8t
t=3 s
Explanation:
Given
Ball is projected horizontally from a building of height ![h=19.6\ m](https://tex.z-dn.net/?f=h%3D19.6%5C%20m)
time taken to reach ground is given by
![\text{Cosidering vertical motion}\\\Rightarrow h=ut+0.5at^2\\\Rightarrow 19.6=0+0.5\times 9.8t^2\\\Rightarrow t^2=4\\\Rightarrow t=2\ s](https://tex.z-dn.net/?f=%5Ctext%7BCosidering%20vertical%20motion%7D%5C%5C%5CRightarrow%20h%3Dut%2B0.5at%5E2%5C%5C%5CRightarrow%2019.6%3D0%2B0.5%5Ctimes%209.8t%5E2%5C%5C%5CRightarrow%20t%5E2%3D4%5C%5C%5CRightarrow%20t%3D2%5C%20s)
(b) Line joining the point of projection and the point where it hits the ground makes an angle of ![45^{\circ}](https://tex.z-dn.net/?f=45%5E%7B%5Ccirc%7D)
From the figure, it can be written
![\Rightarrow \tan 45^{\circ}=\dfrac{h}{x}\\\\\Rightarrow x=h\cdot 1\\\Rightarrow x=19.6](https://tex.z-dn.net/?f=%5CRightarrow%20%5Ctan%2045%5E%7B%5Ccirc%7D%3D%5Cdfrac%7Bh%7D%7Bx%7D%5C%5C%5C%5C%5CRightarrow%20x%3Dh%5Ccdot%201%5C%5C%5CRightarrow%20x%3D19.6)
Considering horizontal motion
![\Rightarrow x=u_xt\\\Rightarrow 19.6=u_x\times 4\\\Rightarrow u_x=4.9\ m/s](https://tex.z-dn.net/?f=%5CRightarrow%20x%3Du_xt%5C%5C%5CRightarrow%2019.6%3Du_x%5Ctimes%204%5C%5C%5CRightarrow%20u_x%3D4.9%5C%20m%2Fs)
(c) The vertical velocity with which it strikes the ground is given by
![\Rightarrow v^2-u_y^2=2as\\\Rightarrow v^2-0=2\times 9.8\times 19.6\\\Rightarrow v=\sqrt{384.16}\\\Rightarrow v=19.6\ m/s](https://tex.z-dn.net/?f=%5CRightarrow%20v%5E2-u_y%5E2%3D2as%5C%5C%5CRightarrow%20v%5E2-0%3D2%5Ctimes%209.8%5Ctimes%2019.6%5C%5C%5CRightarrow%20v%3D%5Csqrt%7B384.16%7D%5C%5C%5CRightarrow%20v%3D19.6%5C%20m%2Fs)
Thus, the ball strikes with a vertical velocity of ![19.6\ m/s](https://tex.z-dn.net/?f=19.6%5C%20m%2Fs)
Answer: They create antibodies.
Answer:
a) Explanation below. b) Explanation below
Explanation:
Torque is defined as the product of a force by a radius, while momentum is defined as the product of force by a distance. Mathematically we would have
T = F * r
M = F * d
where:
T = torque = [N*m]
M = moment = [N*m]
F = force =[N]
d = distance [m]
r = radius [m]
Although they have the same units, the difference between them is the application. For the case of torque this is always applied in parts that are in rotation, such as the shafts of cars, the shafts of pumps, torque in gears and etc. While the moment can be applied to a body without the need for it to rotate.
A couple, is as its name suggests a couple of forces of equal magnitude but opposite sense and do not share a line of action. A body under the action of a couple of forces tends to rotate the body without moving it from one point to another.