Answer:
25.6 m/s
Explanation:
Draw a free body diagram of the sled. There are two forces acting on the sled:
Normal force pushing perpendicular to the hill
Weight force pulling straight down
Take sum of the forces parallel to the hill:
∑F = ma
mg sin θ = ma
a = g sin θ
a = (9.8 m/s²) (sin 38.0°)
a = 6.03 m/s²
Given:
v₀ = 0 m/s
a = 6.03 m/s²
t = 4.24 s
Find: v
v = at + v₀
v = (6.03 m/s²) (4.24 s) + (0 m/s)
v = 25.6 m/s
Answer:
m₁ = 0.37 kg
Explanation:
According to Law of conservation of energy:
Heat Lost by Aluminum = Heat Gained by Water
m₁C₁ΔT₁ = m₂C₂ΔT₂
where,
m₁ = mass of piece of aluminum = ?
C₁ = specific heat capacity of aluminum = 900 J/kg.°C
ΔT₁ = Change in temperature of aluminum = 250°C - 22°C = 228°C
m₂ = mass of water = 9 kg
C₂ = specific heat capacity of water = 4200 J/kg.°C
ΔT₁ = Change in temperature of aluminum = 22°C - 20°C = 2°C
Therefore,
m₁(900 J/kg.°C)(228 °C) = (9 kg)(4200 J/kg.°C)(2°C)
m₁ = (75600 J)/(205200 J/kg)
<u>m₁ = 0.37 kg</u>
B. Inelastic collision.
In elastic collision , both momentum and kinetic energy are conserved while in inelastic collision only momentum is conserved. there is some loss of energy in inelastic collision during collision.
During the collision of bat with baseball, some energy gets lost to heat and sound. hence the kinetic energy is not conserved although the momentum is conserved.
To calculate the work, we use:
W = PΔV
W = 10(0.4-0.01)
W = 3.9 L*atm
W = 3.9 * 101.3
W = 395.07 Joules
