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If the crate isn't accelerating ... i.e. sliding at a constant speed, not speeding up or slowing down ...then the forces on it are balanced. The pseudo-force of friction is 140N in the direction opposite toits speed.
You should have friction between the box and the ground, the force you used to push it, the mass of the object, and gravity. The resistance of the air is neglibible. This should be all the forces on an object on flat ground.
friction
For every action there is an equal and opposite reaction, so if you push on a crate, the crate pushes back with a normal force equal to the force exerted. Thus, expect a force of 50 N to push back at you. However, if you meant the normal force of the ground exerted on the box, then that would included the 50 N force and the weight of the crate.
Is mgsinΘ > μmgcosΘ ? Is sinΘ > μ cosΘ ? Is sin35º > .65 cos35º Is .573 > .532 => Yes, so crate slides down the plane, no matter what the mass is or acceleration due to gravity
If the crate isn't accelerating ... i.e. sliding at a constant speed, not speeding up or slowing down ...then the forces on it are balanced. The pseudo-force of friction is 140N in the direction opposite toits speed.
The direction of friction on the crate is opposite to the direction in which it is sliding. In this case, since you are pushing the crate to the right, the friction will act to the left in order to oppose the motion.
You should have friction between the box and the ground, the force you used to push it, the mass of the object, and gravity. The resistance of the air is neglibible. This should be all the forces on an object on flat ground.
friction
The weight of the crate is acting downward on the ground and the ground is exerting a force equal to the weight of the crate upward on the crate.
The weight of the crate is acting downward on the ground and the ground is exerting a force equal to the weight of the crate upward on the crate.
it does not have enough friction.
For every action there is an equal and opposite reaction, so if you push on a crate, the crate pushes back with a normal force equal to the force exerted. Thus, expect a force of 50 N to push back at you. However, if you meant the normal force of the ground exerted on the box, then that would included the 50 N force and the weight of the crate.
Is mgsinΘ > μmgcosΘ ? Is sinΘ > μ cosΘ ? Is sin35º > .65 cos35º Is .573 > .532 => Yes, so crate slides down the plane, no matter what the mass is or acceleration due to gravity
not enough friction
me
276 Newtons. Coefficient of static friction is a ratio between the force it takes to budge the object over the normal force (mass times gravity). So: 0.69 = Force / 400 N (40 kg times 10 m/s^2, the force of gravity). Solve for 276 N.