Technician a says that for best results, loosen the fastener immediately after spraying it with penetrating oil. technician b says that rusted fasteners may be loosened by tapping with a hammer. which technician is correct?

a. technician a only
b. technician b only
c. both technicians a and b
d. neither technician a nor b

C. Both Technicians A and B

Explanation:

To loosen a fastener immediately especially if it is a rusted one we can follow these steps.

1. Tap the sides of the fastener so that the rust particle fall off.

2. These rust particles can be brushed off.

3. Spray the fastener with the penetrating oil.

4. Again tap the sides with a hammer to let the oil penetrate the inter-locked parts (threads in case of a nut and bolt).

5. Loosen the fastener after oil has penetrated.

Note: It should be kept in consideration that spraying alone won't do the job, tapping is essential to let the oil penetrate deep in to free the rusted parts.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.