Years of research have demonstrated that rats are intelligent creatures who experience pain and pleasure, care about one another, are able to read the emotions of others, and would assist other rats, even at their own expense.
<h3>Experiments:</h3>
In trials carried out at Brown University in the 1950s, rats were trained to press a lever for food, but they stopped pressing the lever when they noticed that with each press, a rat in an adjacent cage would scream in pain (after experiencing an electric shock).
Rats were trained to press a lever to lower a block that was hanging from a hoist by electric shocks administered by experimenters. A rat was subsequently hoisted into a harness by the experimenters, and according to their notes, "This animal normally shrieked and wriggled sufficiently while dangling, and if it did not, it was jabbed with a sharp pencil until it exhibited indications of discomfort." Even if it wasn't in danger of receiving a shock, a rat watching the scenario from the floor would pull a lever to lower the hapless rodent to safety.
Learn more about experiments on rats here:
brainly.com/question/13625715
#SPJ4
This is easily explained saying that the frictional force between the books and the paper isn't big enough to produce a displacement in the books. The displacement in the books doesn't happen because the frictional force between the books and the surface they are standing on is bigger than the paper's one.
Acceleration = (0.2 x g) = 1.96m/sec^2.
<span>Accelerating force on 1kg. = (ma) = 1.96N. </span>
<span>1kg. has a weight (normal force) of 9.8N. </span>
<span>Coefficient µ = 1.96/9.8 = 0.2 minimum. </span>
<span>Coefficient is a ratio, so holds true for any value of mass to find accelerating force acting. </span>
<span>e.g. 75kg = (75 x g) = 735N. </span>
<span>Accelerating force = (735 x 0.2) = 147N</span>
Simply be used as a reference point <span>to describe its position. a fact forming the basis of an evaluation or assessment; criterion. They had few cultural </span>reference points<span> in common.</span>
Answer:
<em>The first choice (32m/s) is the closest to the answer</em>
Explanation:
The magnitude of a vector is the distance between the initial and the end point of the vector.
Being Vx and Vy the horizontal and vertical components of the vector V respectively, the magnitude of V is calculated as:

The components of the velocity of the physics student's projectile launcher are Vx=28 m/s and Vy=15 m/s.
Calculate the magnitude of the velocity:




The first choice (32m/s) is the closest to the answer