Answer:
Speed, mass and acceleration
Explanation:
A scalar quantity is a quantity that has only magnitude but no direction while a vector quantity has both magnitude and direction.
According to the question, the row that has two scalars and one vector is speed, mass and acceleration.
The two scalars in this row are speed and mass while the vector quantity there is the acceleration.
Acceleration has direction since it possess direction. A body accelerating will do so in a particular direction. Speed and mass doesn't possess any direction. Mass only specify the magnitude of the body but no clue as to which direction is the body moving towards.
Speed also only specify the
total distance covered with respect to time but not the direction of the direction.
Answer:
Speed is a "scalar" quantity
(C) is the correct answer
An object could travel at 10 m/s to some point and then return to the origin at 10 m/s for an average speed of 10 m/s, however it's displacement over that time would be zero for a net velocity of zero.
Answer:
F = 614913.88 N
Explanation:
We are given;
Mass of pile driver; m = 1800 kg
Height of fall of pole driver; h = 4.6 m
Depth driven into beam; d = 13.6 cm = 0.136 m
Now, from energy equations and applying to this question, we can write that;
Workdone = Change in potential energy
Formula for workdone is; W = F × d
While the average potential energy here is; W = mg(h + d)
Thus;
Fd = mg(h + d)
Where F is the average force exerted by the beam on the pile driver while in bringing it to rest.
Making F the subject, we have;
F = mg(h + d)/d
F = 1800 × 9.81 × (4.6 + 0.136)/0.136
F = 614913.88 N
