A. 1000
B. 2000
C. 4000
D. 5000
2. A 20kg mass is held 4m above the ground. What is the approximate potential evergy of the mass with respect to the ground?
A. 5J.
B. 50J
C 80J
D. 800J
3. A TV set is pushed a distance of 2m with a force of 20 N that is in the same direcion as the set moves. How mauch work is done on the set?
A. 10J
B. 20J
C. 40J
D. 80J
drwls
answered
Solve for the force
B. P.E. = M g H
C. Work = force x distance
You should know these formulas. You can do the calculations in your head.
desk
answered
c
d
Explain Bot
answered
1. The equation we'll be using for this question is Newton's second law of motion: F = ma, where F is the force, m is the mass, and a is the acceleration. To find the average braking force, we need to determine the deceleration.
We can use the equation v = u + at, where v is the final velocity (which is 0 in this case), u is the initial velocity (10 m/s), a is the acceleration, and t is the time (5 seconds).
Rearranging the equation to solve for acceleration, we have:
0 = 10 + a * 5
Simplifying, we get:
-10 = 5a
a = -2 m/s^2
Now, we can substitute the values into the equation F = ma:
F = 1000 kg * -2 m/s^2
F = -2000 N
Since we are looking for the average braking force (ignoring the negative sign), the answer is B. 2000 N.
2. The potential energy (PE) of an object at a certain height is given by the equation PE = m * g * h, where m is the mass, g is the acceleration due to gravity (approximately 9.8 m/s^2 on Earth), and h is the height.
Substituting the given values, we have:
PE = 20 kg * 9.8 m/s^2 * 4m
PE = 784 J
The approximate potential energy of the mass with respect to the ground is therefore D. 800 J.
3. The work done on an object is given by the equation W = F * d, where W is the work done, F is the force, and d is the distance. Since both the force and the distance are given, we can plug in the values into the equation.
W = 20 N * 2 m
W = 40 J
Therefore, the work done on the TV set is C. 40 J.
I hope this explanation helps! Let me know if you have any further questions.
