Answer:
B.The force of friction between the block and surface will decrease.
Explanation:
The force of friction is given by
where 
is the coefficient of friction and 
is the normal force.
When the student pulls on the block with force 
at an angle 
, the normal force on the block becomes
and hence the frictional force becomes
.
Now, as we increase , 
increases which as a result decreases the normal force 
, which also means the frictional force decreases; Hence choice B stands true.
<em>P.S: Choice D is tempting but incorrect since the weight </em>
<em> is independent of the external forces on the block. </em>
Here is the full information about the question. <span>Ilya and Anya each can run at a speed of 8.50mph and walk at a speed of 3.50 mph . They set off together on a route of length 5.00 miles . Anya walks half of the distance and runs the other half, while Ilya walks half of the time and runs the other half.
the calculation would be:
</span><span>
t = d / s </span>
<span>t = 2.5 (half of the total distance) / 8.5 (speed of running) </span>
<span>This is .294 hours which is about 1058s... </span>
<span>for the walking part... </span>
<span>t = d / s </span>
<span>t = 2.5 / 3.5 </span>
<span>t = 5/7hours = 2571 s. </span>
Answer: Around 364 to 480
Magma<span> is composed of molten rock and is stored in the Earth's crust. </span>Lava<span> is </span>magma<span> that reaches the surface of our planet through a volcano vent. </span>Lava<span>flow, Hawai.</span>
Your hypothesis can be that the group with calculators would finish faster than the group without calculators.
