A child and sled with a combined mass of 54.8 kg slide down a frictionless hill that is 11.5 m

high at an angle of 36 degrees

from horizontal.

The acceleration of gravity is 9.81 m/s^2.

If the sled starts from rest, what is its speed

at the bottom of the hill?

Answer in units of m/s.

15.02 m/s.

Explanation:

Given that the height of the hill, h= 11.5 m.

Combined mass, m= 54.8 kg

The initial velocity of the combined mass, u=0

Acceleration due to gravity, .

Angle of the path the horizontal, degree.

Let A be the initial position and B be the final position of the sled as shown in the figure.

The path is frictionless so the drag force =0

The gravitational force acting on the combined mass in the downward direction,

The component of force acting in the direction of motion =

Let be the acceleration of the combined mass, m, So,

[ from equation (i)]

Let v be the final velocity of the combined mass.

Now, by using the equation of motion,

Here, s is the displacement in the direction of motion,

So, s= AB

Now, in the right-angled triangle ABO,

Now,  from equations (ii), (iii) and (iv), we have

By using the given values, we have

Hence, the speed of the combined mass at the bottom = 15.02 m/s.

current and voltage can both be different in different parts of a circuit so it matters where you place the ammeter and voltmete