Answer:
a) 37.8 W
b) 2 Nm
Explanation:
180 g = 0.18 kg
We can also convert 180 revolution per minute to standard angular velocity unit knowing that each revolution is 2π and 1 minute equals to 60 seconds
180 rpm = 180*2π/60 = 18.85 rad/s
We can use the heat specific equation to find the rate of heat exchange of the steel drill and block:

Since the entire mechanical work is used up in producing heat, we can conclude that the rate of work is also 37.8 J/s, or 37.8 W
The torque T required to drill can be calculated using the work equation



Because force always has a direction, it always works towards or against something.
you might know that force,
is rate of change of momentum i.e
force = m (v-u)/t
= (mv - mu )/ t
as we know momentum is a vector quantity so, the rate of change of momentum i.e Force would also be a vector quantity.
momentum = mass × velocity
velocity has a direction so,
momentum has also got a direction.
so, momentum is also a vector quantity.
The characteristics of the velocity vector used to find the results for the direction of acceleration and velocity are:
- Acceleration is towards the center of the circle
- The velocity is tangent to the circle counterclockwise.
Newton's Second Law establishes a relationship between force, mass and acceleration of bodies.
<h3>Centripetal acceleration.
</h3>
In the case of circular motion there is a constant change in the direction of the velocity vector, even when its module remains constant, this change in direction points towards the center of the circle, so that the module is constant.
They indicate that the satellite is moving counterclockwise, therefore the speed must go to the left (counterclockwise) tangential to the circle.
In conclusion using the characteristics of the velocity vector we can find the results for the direction of acceleration and velocity are:
- Acceleration is towards the center of the circle
- The velocity is tangent to the circle counterclockwise.
Learn more about centripetal acceleration here: brainly.com/question/25243603
Answer:
scientists will use absolute dating to find how old a fossil exactly is.
Answer:
The idea behind space expansion is that after the big bang, the universe started infinitely expanding. It's also called metric expansion. Stephen Hawking's A Brief History of Time goes further into detail on this.