Answer:
8 seconds
Explanation:
Answer:
Explanation:
Going up
Time taken to reach maximum height= usin∅/g
=3 secs
Maximum height= H+[(usin∅)²/2g]
=80+[(60sin30)²/20]
=125 meters
Coming Down
Maximum height= ½gt²
125= ½(10)(t²)
t=5 secs
Answer:
Friction between the box and the floor is 25N to the left
Explanation:
There are two forces acting on the box along the horizontal direction:
- The force of push applied by the worker, in the forward direction, F
- The force of friction, , acting in the opposite direction (backward)
So the net force acting on the box is
According to Newton's second law of motion, the net force on an object is equal to the product between its mass (m) and its acceleration (a), so we can write:
And so
However, in this case the box is moving at constant speed; this means that its acceleration is zero:
Therefore we have:
Which means
And since we are told that
This means that the force of friction is also 25 N:
That's one of the three changes that are called "acceleration".
The other two are:
-- increase in the magnitude
-- change in direction.
Some might call a decrease in the magnitude "deceleration".
Answer:
The resultant velocity of the plane relative to the ground is;
150 kh/h north
Explanation:
The flight speed of the plane = 210 km/h
The direction of flight of the plane = North
The speed at which the wind is blowing = 60 km/h
The direction of the wind = South
Therefore, representing the speed of the plane and the wind in vector format, we have;
The velocity vector of the plane = 210.
The velocity vector of the wind = -60.
Where, North is taken as the positive y or direction
The resultant velocity vector is found by summation of the two vectors as follows;
Resultant velocity vector = The velocity vector of the plane + The velocity vector of the wind
Resultant velocity vector = 210. + (-60.) = 210. - 60. = 150.
The resultant velocity vector = 150.
Therefore, the resultant velocity of the plane relative to the ground = 150 kh/h north.
Answer:
the force is perpendicular to the speed, it is a type of force that changes the direction of the speed, as in the uniform circular motion te, but does not change its modulus.
Explanation:
The magnetic force is given by the expression
F = q v x B
The bold are vectors, where v is the velocity and B is the magnetic field, the product is the cross product whose result is a vector perpendicular to the two vectors (v and B)
From the above, the force is perpendicular to the speed, it is a type of force that changes the direction of the speed, as in the uniform circular motion te, but does not change its modulus.
Even when the change in direction is real and is caused by a centripetal force
For there to be a change in the velocity modulus there must be a force parallel to the velocity direction, generally a force in electrical