can you help me with some physics questions( magnitude of friction and acceleration)?

[emily K]

I'm taking an online physics course and couldn't find information in the book about these problems. Any help would be appreciated.
1) If you pull horizontally on a block and it slides across the floor, continually gaining speed, the friction is opposite to your pull. The magnitude of the friction acting on the block is ____ your pull. ( I think my teacher means opposite or the same as)
2) The acceleration of a truck that moves at a steady velocity of 50 km/h for 50 seconds is _______.

[Zowne]

1) The question states that the block is gaining speed as it is being pulled. This means that the force from the friction, and the force from pulling are not equal. Because it is GAINING speed, the force on the block must be greater in the direction of pull, than the direction of the force of friction.
Hence "The magnitude of the friction acting on the block is less than your pull"

2) If the truck is moving at a STEADY velocity, then there is no acceleration.
i.e. "The acceleration of a truck that moves at a steady velocity of 50 km/h for 50 seconds is 0m/s/s"

[Roby]

1) the magnitude of the friction is < than your pulling force.
- If it was equal to the pulling force, the block would remain
in that place, there would be no movement;
- if it was greater than the pulling force, the block would
move backward.
2) 0 km/h.
- the acceleration is the increase of speed per each
second. If the speed remains costant, the acceleration is
therefore zero.

let me know if you need any help!
good luck!