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>
1250kgm²/s is the motional kinetic energy of a 25kg object moving at a speed of 10m/s
Kinetic energy of an object is defined as the energy which is possessed when that is in motion. It is the energy of the kinetic mass of an object. Kinetic energy is never negative and is a scalar quantity. That is, it shows only size, not orientation.
Given to us
Mass of the object, m=25kg
Velocity of the object, v=10m/s
K.E=1/2x25x10²
=1250
Kinetic energy is directly proportional to the mass and velocity squared (K.E.) of an object. =1/2xMxV². If the mass is in kilograms and the velocity is in meters/second, then the kinetic energy is in kilograms - meters squared/second.
Learn ore about Kinetic energy here brainly.com/question/25959744
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Compression and rarefaction are two phenomenon occurs in longitudunal wave!
when there is denser particle gathering in that wave , there we called it compression and the rarer part of particles is rarefaction !
The answer is the FIRST OPTION
Work occurs when a force is applied to an object and the object moves in the direction of the force applied <span />