Answer:
The frictional force acted on mass, m = 7.5 kg
Explanation:
Given data,
The acceleration of the box, a = 2 m/s²
The force acting on the box, F = 15 N
The mass of the box, m = ?
The force is defined as the product of mass and acceleration.
F = m x a newton
Therefore,
m = F / a
= 15 / 2
= 7.5 kg
Hence, the frictional force acted on mass, m = 7.5 kg
Answer:
The speed of the kid and the skateboard together is 0.723 m/s
Explanation:
Let the mass of the kid be
Let the mass of the skateboard be
The initial speed of the skateboard,
The initial horizontal speed of the boy as he jumps on the skateboard,
Let the speed of the kid and the skateboard together be v
According to the principle of conservation of momentum:
Substituting the appropriate values into the given equation
36 = 49.8 v
v = 36/49.8
v = 0.723 m/s
Answer:
P = W / t = m g s / t = m g v where work by auto = m g s
30 kw = 30000 watts = 30000 J / s
Work wasted = F v as shown above relating work and power
Work done against incline = m g s sin 8.75 and power against incline
= m g v sin 8.75 = 1222 v Joules / sec
power in moving auto = power available - power lost to friction
power in moving auto = 30000 - resistance = 30000 - 910 v
1222 v = 30000 - 910 v
v = 30000 / 2132 = 14 m/s
Note: constant resistance to motion must mean P = W / t = F s / t = F v
Answer:
C i think sorry if inmccorect
Explanation: