Hey I need help can someone help me out, please

According to the work-energy theorem, the change in the kinetic energy of the combined mass of the child and the sled, is equal to the total work done on the object by external forces.
The external forces capable to do work on the combination of child +sled, are the friction force (opposing to the displacement), and the component of the weight parallel to the slide.
As this last work is just equal to the change in the gravitational potential energy (with opposite sign) , we can write the following equation:

$\Delta K + \Delta U = W_{nc} (1)$

ΔK, is the change in kinetic energy, as follows:

$\Delta K = \frac{1}{2}* m* (v_{f} ^{2} - v_{0} ^{2}) (2)$

ΔU, is the change in the gravitational potential energy.
If we choose as our zero reference level, the bottom of the slope, the change in gravitational potential energy will be as follows:

$\Delta U = 0 - m*g*h = -m*g*d* sin\theta (3)$

Finally, the work done for non-conservative forces, is the work done by the friction force, along the slope, as follows:

$W_{nc} = F_{f} * d * cos 180\º \\\\ = 0.2*m*g*d* cos 180\º = -0.2*m*g*d (4)$

Replacing (2), (3), and (4) in (1), simplifying common terms, and rearranging, we have:

$\frac{1}{2}* (v_{f} ^{2} - v_{0} ^{2}) = g*d* sin\theta -0.2*g*d$

Replacing by the givens and the knowns, we can solve for sin θ, as follows: $\frac{1}{2}*( (4.30 m/s) ^{2} - (0.75 m/s)^{2}) = 9.8 m/s2*25.5m* sin\theta -0.2*9.8m/s2*25.5m\\ \\ 8.56 (m/s)2 = 250(m/s)2* sin \theta -50 (m/s)2\\ \\ sin \theta = \frac{58.6 (m/s)2}{250 (m/s)2} = 0.236$ ⇒ θ = sin⁻¹ (0.236) = 13.7º

8 0

3 years ago

Draw Aufbua diagram of sodium ion

Mazyrski [523]

Answer:

Aufbau diagram of sodium ion:

2s²,2p⁶,3s¹

5 0

3 years ago

(iv) Rank the capacitors in part (i) in the order of the energy they store.

prohojiy [21]

The rank of the capacitors in order of the energy they store is E>A>B>D>C.

<h3>What is capacitor?</h3>

In an electric field, a capacitor is a device that stores electrical energy. It has two terminals and is a passive electrical component.

Capacitance refers to a capacitor's effect. While there is some capacitance between any two nearby electrical wires in a circuit, a capacitor is a component made to increase capacitance. The term "condenser" or "condensator" originally applied to the capacitor. Condenser microphones, sometimes known as capacitor microphones, are a remarkable exception to the general lack of usage of this name and its cognates in English.

Practical capacitors come in a wide variety of physical shapes and constructions, and there are numerous varieties that are used often.

To learn more about capacitor,visit:

brainly.com/question/17176550

#SPJ4

5 0

2 years ago