Density = mass / volume ;
1 Cubic Centimeter = 0,000001 Cubic Meter
8 cm^3 = 0.000008 m^3
12,9 g = 0,0129 kg

The density is 0,0129 kg/ 0,000008 m^3 = <span><u>1612,5 kg/m^3</u> </span>

4 0

4 years ago

Two ice skaters, Lilly and John, face each other while at rest, and then push against each other's hands. The mass of John is tw

seropon [69]

Answer:

Lilly's speed is two times John's speed.

Explanation:

m = Mass

a = Acceleration

t = Time taken

u = Initial velocity

v = Final velocity

The force they apply on each other will be equal

$F=ma\\\Rightarrow a_l=\frac{F}{m_l}$

$F=ma\\\Rightarrow a_j=\frac{F}{2m_l}\\\Rightarrow a_j=\frac{1}{2}a_l$

$v=u+at\\\Rightarrow v_l=0+\frac{F}{m_l}\times t\\\Rightarrow v_l=a_lt$

$v=u+at\\\Rightarrow v_l=0+\frac{F}{2m_l}\times t\\\Rightarrow v_j=\frac{1}{2}a_lt\\\Rightarrow v_j=\frac{1}{2}v_l\\\Rightarrow v_l=2v_j$

Hence, Lilly's speed is two times John's speed.

4 0

3 years ago

A child dangles a 1.50-kilogram stuffed toy 0.500 meters from the ground. What is the potential energy of the toy?

inn [45]

Since we know that
Gravitational potential energy = mass × height ×gravity

then

GPE = 1.5 kg x 0.500 m x 9.8m/s^2

therefore

GPE = 7.35 J

6 0

3 years ago

Read 2 more answers

find the speed of a rolling ball that travels a distance of 10 m over the top of a smooth table in 2.0 seconds

umka21 [38]

The speed is between 5-15

4 0

3 years ago

Read 2 more answers