Answer:
Newton's F=ma, which means the force (F) acting on an object is equal to the mass (m) of an object times its acceleration (a)
Answer:
the maximum vertical height the person in the cart can reach is 18.42 m
Explanation:
Given;
mass of the person in cart, m₁ = 45 kg
mass of the cart, m₂ = 43 kg
acceleration due to gravity, g = 9.8 m/s²
final speed of the cart before it goes up the hill, v = 19 m/s
Apply the principle of conservation of energy;
Therefore, the maximum vertical height the person in the cart can reach is 18.42 m
Answer:
The kinetic energy of the cell phone is 9J
Explanation:
The kinetic energy is the energy possessed by a body by virtue of motion.
The kinetic energy is expressed as
KE= 1/2m(v)²
Given data
Mass of cell phone m= 80g--to kg=80/1000= 0.08kg
Velocity of cell phone v= 15m/s
Substituting our given data we have
KE= 1/2*0.08(15)²
KE= (0.08*225)/2
KE=18/2
KE= 9J
Answer:
4452.5 J.
Explanation:
The diver have both kinetic and potential energy.
Ek = 1/2mv² ................. Equation 1
Where Ek = Kinetic Energy of the diver, m = mass of the diver, v = velocity of the diver.
Given: m = 65 kg, v = 6.4 m/s.
Substitute into equation 1
Ek = 1/2(65)(6.4²)
Ek = 1331.2 J.
Also,
Ep = mgh ............................ Equation 2
Where Ep = Potential energy of the diver when its above the water, h = height of the diver above the water, g = acceleration due to gravity.
Given: m = 65 kg, h = 4.9 m, g = 9.8 m/s²
Substitute into equation 2.
Ep = 65(4.9)(9.8)
Ep = 3121.3 J.
Note: When she hits the water, the potential energy is converted to kinetic energy.
E = Ek+Ep
Where E = Kinetic energy of the diver when she hits the water.
E = 1331.2+3121.3
E = 4452.5 J.
This question is based on the fundamental assumption of vector direction.
A vector is a physical quantity which has magnitude as well direction for its complete specification.
The magnitude of a physical quantity is simply a numerical number .Hence it can not be negative.
A negative vector is a vector which comes into existence when it is opposite to our assumed direction with respect to any other vector. For instance, the vector is taken positive if it is along + X axis and negative if it is along - X axis.
As per the first option it is given that a vector is negative if its magnitude is greater than 1. It is not correct as magnitude play no role in it.
The second option tells that the magnitude of the vector is less than 1. Magnitude can not be negative. So this is also wrong.
Third one tells that a vector is negative if its displacement is along north. It does not give any detail information about the negativity of a vector.
In a general sense we assume that vertically downward motion is negative and vertically upward is positive. In case of a falling object the motion is vertically downward. So the velocity of that object is negative .
So last option is partially correct as the vector can be negative depending on our choice of co-ordinate system.
