F = ma
You need to rearrange this equation to find mass so you would have the equation :
M = f/a
Input the numbers into the equation :
M = 56/7
M = 8
Since static friction is the minimum force required to just start the motion of a stationary object.
Here if we need to start an object from rest then we required F = 700 N
So for the first part of the above problem Force will be F = 700 N
Now if the box is already moving then we will have to use kinetic friction force between box and floor
now we can write the equation of net force as

here



now we will have


Answer:
100 m/s
Explanation:
Mass the mass of Bond's boat is m₁. His enemy's boat is twice the mass of Bond's i.e. m₂ = 2 m₁
Initial speed of Bond's boat is 0 as it won't start and remains stationary in the water. The initial speed of enemy's boat is 50 m/s. After the collision, enemy boat is completely stationary. Let v₁ is speed of bond's boat.
It is the concept of the conservation of momentum. It remains conserved. So,

Putting all the values, we get :

So, Bond's boat is moving with a speed of 100 m/s after the collision.
Answer: 8Ω
Explanation:
Since there are two resistors of 4Ω
connected in series, the total resistance (Rtotal) of the circuit is the sum of each resistance.
i.e Rtotal = R1 + R2
R1 = 4Ω
R2 = 4Ω
Rtotal = ?
Rtotal = 4Ω + 4Ω
Rtotal = 8Ω
Thus, the total resistance of the circuit is 8Ω