Answer:
Water
Explanation:
Because it does not conduct much energy.
Draw something similar to which has more mass in density. For example, a bowling ball and a volley ball. Both substances are similar in size but the bowling ball feels heavier than the volleyball. Label volleyball for less density and bowling ball with more density.
Block on the incline:
• net force parallel to the incline
∑ <em>F</em> (para.) = <em>m₁ g</em> sin(38°) - <em>T</em> = <em>m₁ a</em>
where <em>T</em> is the magnitude of tension in the cord.
Notice that we take down-the-incline to be the positive direction, so that if the 3.9-kg block pulls the 2.6-kg block upwards, then the acceleration of the system is positive.
Suspended block:
• net vertical force
∑ <em>F</em> (vert.) = <em>T</em> - <em>m₂</em> <em>g</em> = <em>m₂</em> <em>a</em>
<em />
Solve both equations for the acceleration <em>a</em>, set the results equal to one another, and solve for <em>T</em> :
<em>a</em> = <em>g</em> sin(38°) - <em>T</em>/<em>m₁</em>
<em>a</em> = <em>T</em>/<em>m₂</em> - <em>g</em>
==> <em>g</em> sin(38°) - <em>T</em>/<em>m₁</em> = <em>T</em>/<em>m₂</em> - <em>g</em>
==> <em>T</em> (1/<em>m₂</em> + 1/<em>m₁</em>) = <em>g</em> (sin(38°) + 1)
==> <em>T</em> = <em>g</em> (sin(38°) + 1) / (1/<em>m₂</em> + 1/<em>m₁</em>)
==> <em>T</em> = (9.81 m/s²) (sin(38°) + 1) / (1/(2.6 kg) + 1/(3.9 kg)) ≈ 25 N