I think answer is A. The Brightness of a Star
The radar device determines the vehicle's instantaneous speed.
I would argue that the purpose of the device is not to determine
whether individuals are driving safely. They only determine whether
individuals are driving within legal speed limits. There's much more
to 'safe' driving than that, but the radar gun can't detect it.
Answer:
Explanation:
horizontal component of velocity of throw = 20 cos20 = 18.8 m /s
vertical downwards component = 20 sin20 = 6.84 m /s
time to displace by height 30 m = t , initial velocity u = 6.84 m /s
h = ut + 1/2 gt²
30 = 6.84 t + .5 x 9.8 t²
4.9 t² + 6.84 t - 30 = 0
t = - 6.84 ±√( 6.84² + 4 x 4.9 x 30 ) / 2x 4.9
= - 6.84 ±√( 46.78 + 588 ) / 9.8
= - 6.84 ±√(634.78 ) / 9.8
= - 6.84 ±25.2 / 9.8
= 1.87 s
horizontal displacement in 1.87 s
= 18.8 x 1.87
= 35.15 m .
"A" I think, not sure tho.
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.