The height of the ball when lifted is given by 7sin(25)=2.96
the gravitational energy is mgh, the kinetic is (1/2)mv². We can set these equal since the pendulum doesn't lose much energy
mgh = (1/2)mv²
we can divide by m (since we don't have it anyways)
gh = v²/2
v=√(gh/2) = √(9.81*2.96/2)=3.8m/s.
Not exactly one of your choices, but the right one none the less
Current = Power/Voltage. 70W/120v= 0.583 Amps.
Answer:
μs = 0.75
μk = 0.58
Explanation:
From a force diagram:
(1)
(2)
When it starts slipping, friction force is the maximum and acceleration is 0. Replacing these conditions on (1):
Solving for μs:
μs = tan 36.7° = 0.75
When it moves at constant speed, friction force is kinetic friction and acceleration is 0. With these conditions the coefficient is:
μk = tan 30.1° = 0.58
A solid object is found to weigh 4.784.78n in air. when it is weighed while fully immersed in water, its apparent weight is 2.482.48n. 983 is the density of the object.
The substance's density is defined as its mass per unit of volume (volumetric mass density or specific mass). Although the Latin letter D may also be used, the symbol for density that is most usually used is (the lower case Greek letter rho). where V is the volume, is the density, and m is the mass. Weight per unit volume is a common informal definition of density, however this is incorrect scientifically; the actual term is specific weight. The US oil and gas industry serves as one illustration of this. A pure substance's mass concentration in numbers is equal to its density. To make density comparisons between different systems of units easier, it is occasionally replaced by the dimensionless quantity "relative density" or "specific gravity," which is the ratio of the density of the material to that of a standard material, usually water. If a substance's relative density to water is less than one, it will float in it. Temperature and pressure have an impact on a substance's density. This variation is frequently not very noticeable for solids and liquids, but it is very noticeable for gases. As pressure is applied, an object's density rises, which reduces the object's volume. With a few rare exceptions, as temperature increases, a substance's density decreases as its volume grows.
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Given that:
Energy of bulb (Work ) = 30 J,
Time (t) = 3 sec
The power consumption = ?
We know that, Power can be defined as rate of doing work
Power (P) = Work(Energy supplied) ÷ time
= 30 ÷ 3
= 10 Watts
<em> The power consumption is 10 W.</em>
