Answer:
7800 J
Explanation:
Heat needed = mass of copper x specific heat of copper x change in temperature
Change in temperature = 30ºC - 20ºC = 10ºC
Specific heat of copper = 390 J/kgºC
Mass of copper = 2 Kg
Substituting the given values in above equation, we get –
Heat needed = 2 Kg x 390 J/kgºC x 10ºC
= 7800 J
<span>Circumference = 2 * pi * r
62.8318 = 2 * 3.14159 * 10 cm
62.8318 * 15 rotations / 42 seconds = 22.44 cm / second
22.44 cm / 100 cm per meter = .2244 m / s</span>
We have to add two vectors.
Vector #1: 0.15 m/s north
Vector #2: 1.50 m/s east
Their sum:
Magnitude: √(0.15² + 1.50²)
Magnitude = √(0.0225+2.25)
Magnitude = √2.2725
Magnitude = <em>1.5075 m/s</em>
Direction = arctan(0.15/1.50) north of east
Direction = <em>5.71° north of east</em>
Answer:
4.9 m/s
Explanation:
Since the motion of the ball is a uniformly accelerated motion (constant acceleration), we can solve the problem by using the following suvat equation:
where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance covered
For the ball in this problem,
u = 0 (it starts from rest)
is the acceleration
s = 3 m is the distance covered
Solving for v,
The gravitational force between two masses is given by:
where
G is the gravitational constant
m1 and m2 are the two masses
r is the separation between the two masses
We see that the force is proportional to the inverse of the square of the distance:
therefore, if the distance is tripled:
r'=3r
The force decreases by a factor 1/9:
Since the original force was 36 N, the new force will be