Answer: part a) both the tension and gravity vectors will be pointing downwards.
part b) the tension vector will be pointing upwards and the gravity will be pointing downwards.
Explanation:
part a) Since you are looking at the FBD for the steel cable here, the tension will be pointing downwards because the girder is hung from the cable which creates a downwards tension. Gravity will always point downwards, to the ground.
part b) Since you are looking at the FBD for the girder here, the tension will be pulled upwards because the cable is weighted which creates an upwards tension. Gravity will always point downwards, to the ground.
Sorry for the poor explanation, but hopefully this makes sense.
Kinetic energy = 1/2 (mass)*(velocity)^2
ke = 1/2 (1500kg) (17m/s)^2
ke = 216750 kg*m^2/s^2 = 216750 Joules
(sorry, I don't know significant figures. but this is otherwise the correct answer with the right units. hope this helps!! :))
The cells are called insibatss, I think I spelled that right but
To calculate the average acceleration of the ball we use the formula,
Here, 
is the final velocity of the ball and 
is the initial velocity of the ball t is the time in contact with the wall.
Given 
towards the wall and 
away from the wall and 
.
Substituting these values in above formula , we get
Here is negative because ball is moving away from the wall.
Therefore, average acceleration of the ball is 
(away from the wall).
