The magnitude of the kinetic friction force, ƒk, on an object is. Where μk is called the kinetic friction coefficient and |FN| is the magnitude of the normal force of the surface on the sliding object. The kinetic friction coefficient is entirely determined by the materials of the sliding surfaces. hope it helps
Answer:
2.1 rad/s
Explanation:
Given that,
Mass of a tether ball, m = 0.546 kg
Length of a rope, l = 4.56 m
The maximum tension the rope can withstand before breaking is 11.0 N
We need to find the maximum angular speed of the ball. Let v is the linear velocity. The maximum tension is balanced by the centripetal force acting on it. It can be given by :
Let 
is the angular speed of the ball. The relation between the angular speed and angular velocity is given by :
So, the maximum angular speed of the ball is 2.1 rad/s.
Of the list, Ultraviolet waves have the shortest wavelength
Answer:
20.179 x 10⁶ J /kg
Explanation:
The food after the reaction gives out heat which increases the temperature of water and air in the reaction chamber . The heat absorbed by water and air gives the estimate of energy content of the food.
Heat absorbed by water = mass x specific heat x rise in temperature
= 3 x 4.18 x 10³ x 3.2
= 40.128 x 10³ J
Heat absorbed by air = mass x specific heat x rise in temperature
0.1 x 3. 2 x .718 x 10³
= 0.23 x 10³
Total heat energy evolved
= 40.358 x 10³ J
This energy is evolved by 2 x 10⁻³ kg of food
energy content per kg of food
= 40.358 x 10³ / 2 x 10⁻³
= 20.179 x 10⁶ J /kg
