Answer:
207.4 N
Explanation:
The torque 
on a body is
where r is the radius vector from the point of rotation to the point at which force F is applied.
The product of r and F is equal to the product of magnitude of r and F multiplied by the sine of angle between both vectors.
Therefore, torque is also given by
Where 
is the angle between r and F.
Use the expression of torque.
Substitute L for r in the equation
Where L is the length of the wrench.
Making F the subject
Force required to pull the wrench is given as,
Substitute 
for , 25 cm for L, and 115o for
Answer:
The rule for kilometers is that every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.
Explanation:
In order to use the rule of thumb to find the speed of sound in meters per second, we need to use some conversion ratios. We know there is 1 mile per every 5 seconds after the lightning is seen. We also know that there are 5280ft in 1 mile and we also know that there are 0.3048m in 1ft. This is enough information to solve this problem. We set our conversion ratios like this:
notice how the ratios were written in such a way that the units got cancelled when calculating them. Notice that in one ratio the miles were on the numerator of the fraction while on the other they were on the denominator, which allows us to cancel them. The same happened with the feet.
The problem asks us to express the answer to one significant figure so the speed of sound rounds to 300m/s.
For the second part of the problem we need to use conversions again. This time we will write our ratios backwards and take into account that there are 1000m to 1 km, so we get:
This means that for every 3.11s there will be a distance of 1km from the place where the lightning stroke. Since this is a rule of thumb, we round to the nearest integer for the calculations to be made easily, so the rule goes like this:
The rule for kilometers is that every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.
Lithium-Ion batteries are commonly used in portable electronics and electric vehicles. These rechargeable batteries have two electrodes: one that's positively charged and contains lithium and another negative one that's typically made of graphite.
Answer:
v = 3.00 x 10⁸ m/s
Explanation:
given,
speed of light in vacuum = 299,792,458 m/s
speed of light in scientific notation to three significant figures
v = 2.99792458 x 10⁸ m/s
by rounding off the speed to three significant figure.
v = 3.00 x 10⁸ m/s
On the fourth place the value is greater than 5 so, on the third place 1 will be added.
now, the speed with three significant figure comes out to be
v = 3.00 x 10⁸ m/s
