Physics True/False.. pls check my answers!?

Question

Hi, I only have 1 chance to get this right. Correct me pls.

A) The kinetic energy of an object depends on the direction of the motion involved.

False, KE=1/2mv^2, the ^2 cancels any +/- involved in vectors.

B) The kinetic energy can never be negative.

False, same reasoning as above.

C) The work done by a constant force acting on an object is independent of the orientation of the force relative to the motion of the object

False, if an object's force opposes, the motion, the work done is negative??? not sure

D) The work-energy principle is not valid if there are frictional forces acting.

True, friction is converted into heat and the system KE=PE, so the sys loses energy

E) Work cannot be done in the absence of motion.
False, W=fd, and if d=0, then W=0

F) The work done to raise a box onto a platform depends on how fast it is raised. (Neglect friction, assume it starts on the ground at rest, and ends up resting on the platform)

False, because it

Answer 1

d is not correct and nor is f,the rest are.
F)Work depends on force and distance,Force depends on mass and accleration.
If the box is raised quickly then accleration is more(constant velocity is not mentioned)and hence w is different.
D)Frictional forces are considered,how do u think anything moves.

Answer 2

I think B is true, because as you stated in A the ^2 would make all answers positive, which I agree with because I've never seen energy to be a negative value. C is false because the angle at which the force is applied affects the impact of the force. E is true because if you don't have motion, then you don't have distance and if distance is 0, then work is 0.

Answer 3

you would be able to desire to make certain in case your solutions are top? regrettably you probably did no longer comprise your solutions which makes human beings think of you probably did no longer easily attempt fixing the topics. a million. internet tension = ma. the stress of friction is opposite path via fact the utilized tension. 2. comparable subject as #a million, different than the frictional tension is given instead of the utilized tension and the numbers are diverse. 3. comparable as #a million (in basic terms diverse numbers) 4. what does it propose, the rocket is "fried"? back, it is the comparable type of subject. yet instead of utilized and frictional tension, you have utilized (the thrust) and gravitational tension (mg). the thrust is upward, gravitational tension is downward.

Answer 4

I did not see any problems

Answer 5

Have your teacher correct it

Answer 6

there should be nothing wrong, if i m right

Answer 7

True, true.