Answer:
a)The direction the frictional force will acts is in the positive x direction.
Explanation:
a)The direction the frictional force will acts is in the positive x direction
b)in the horizontal direction, the total force F(total) is equal to 4times the frictional force in the wheel.
F(total)=4f
''f'' is taken as the frictional force.
c)4times the normal force on each wheel minus the acceleration equals zero i.e 4N(wheel)-a=0
=4N(wheel)-mg=0
d) torque is the force that tends to bend rotation
ζ=rf
but acceleration=4×frictional force
cross multiply
f=ζ/r
f=ma/4
ma/4=ζ/r
a=4ζ/r
It is Potential energy it's at rest
<span>If my memory serves me well, sensory receptors which would lead you to squint in bright light are called </span><span>C. photoreceptors</span>
The impulse required to decrease the speed of the boat is equal to the variation of momentum of the boat:

where
m=225 kg is the mass of the boat

is the variation of velocity of the boat
By substituting the numbers into the first equation, we find the impulse:

and the negative sign means the direction of the impulse is against the direction of motion of the boat.