2007-01-24 19:56:26 · 7 answers · asked by adonis d 1 in Science & Mathematics ➔ Physics
Newton's second law of motion defines force as mass times acceleration. The sign of the force is the same as the sign of the acceleration. For instance, if a ball is dropped under gravity then the sign is positive if increasing values downwards are considered positive.
2007-01-24 20:02:16 · answer #1 · answered by pUnkInner 2 · 0⤊ 0⤋
Dear friend,
Newton's second law of motion is mathematically stated as F=ma.Where F is the force causing motion,m-the mass of the body moved,a-the acceleration.Acceleration a is always in the direction of the resultant force f applied.So it has to be positive.But in some enginnering and real life problems we may be forced to adopt one direction as positive and the other as negative.For example a bus moving from town 1 to town 2.We are interested in finding out the acceleration in some time interval t.If the final velocity is lower than the initial velocity in the time interval t considered,then the acceleration carries a negative sign.Instead it is called as deceleration with a positive sign.But even then as per Newton's 2 law of motion,the negative acceleration or deceleration is due to a corresponding negative force(ie. force opposing motion) in the form of friction or brakes applied.Two negatives make a positive or the resulting acceleration is in the direction of the opposing force and therefore taken as positive in F'=ma' where F'-opposing negative force and a'-corresponding negative acceleration.
2007-01-24 20:38:32 · answer #2 · answered by karthik ramnarayan 2 · 0⤊ 0⤋
a million. Acceleration is fee of substitute of speed, so even however speed is 0, that's changing (from going as much as happening) so it particularly is acceleration isn't 0. it particularly is 9.8 m/s² 2. F = sum of forces = 12N north + 15N south = 3N south (12 of the south newtons are cancelled by using the north newtons because they are in opposite guidelines)
2016-12-12 19:48:11 · answer #3 · answered by ? 4 · 0⤊ 0⤋
The sign is positive, the symbol is usually "a": F = m*a. Positive sign means acceleration is in the same direction as the force.
2007-01-24 20:15:51 · answer #4 · answered by gp4rts 7 · 0⤊ 0⤋
acceleration=dV/dt
i.e rate of change of velocity.So with time velocity can decrease or increase or may be constant.
acceleration is always positive as word mean in genral english language.
when there is decrease in velocity due to external force , it is RETARDATION.
2007-01-24 20:06:04 · answer #5 · answered by rajeev_iit2 3 · 0⤊ 0⤋
m/s^2
is that what you want to know ?
2007-01-24 20:16:54 · answer #6 · answered by Anonymous · 0⤊ 0⤋
its an alpha
2007-01-24 20:03:41 · answer #7 · answered by insane killer 1 · 0⤊ 0⤋