(d) you observe someone pulling a block of mass 41 kg across a low-friction surface. while they pull a distance of 4 m in the direction of motion, the speed of the block changes from 5 m/s to 7 m/s. calculate the magnitude of the force exerted by the person on the block.

The magnitude of the force is 124.23 N.

Explanation:

To known the magnitude of the force is necessary to find the acceleration, that can be done by means of the equations for a a Uniformly Accelerated Motion:

 (1)

Where is the final velocity, is the initial velocity, a is the acceleration and t is the time.  

(2)

(3)

By replacing (2) in equation (3) it is gotten:

Therefore, by subtracting the first and third term ( ⇒ ) it is got:

Applying common factor for :

 (4)

Equation (4) can be rewritten in terms of t:

By knowing the time is possible to determine the acceleration by means of equation (2):

The magnitude of the force exerted by the person on the block can be determine by means of Newton's second law:

(5)

Hence, the magnitude of the force is 124.23 N.

im sorry i dont know

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft