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>
Answer:
Speed in km/hr will be 109.412 km/hr
Explanation:
We have given speed of the car on a highway = 68 mi/hr
We have to find the speed in km/hr
For this first we have to change mi to km
We know that 1 mile = 1.609 km
Speed is the ratio of distance and time
So 68 mi/hr
So the speed in km/hr will be 109.412 km /hr