Calculate the net force, acceleration, or mass in each situation:

Question

a) A 72 kg rugby player accelerates at 1.6 m/s2
[forward].
b) A 2.3 kg model rocket accelerates 12 m/s2
[up].
c) A cannon exerts a force of 2.4 x 104 N [E] on a 5.0 kg shell.
d) (b) A hockey stick hits a 160 g puck forward with a force of 24 N.
e) A driver brakes and the car accelerates at 1.2 m/s2
[backwards]. The net force on the car is 1400 N
[backwards].
f) A woman throws a shot put with a net force of 33 N [forward] with an acceleration of 6.0 m/s2
[forward].

Answer 1

To calculate the missing values, we can use Newton's second law of motion:

a) Given the mass (m) of the rugby player as 72 kg and the acceleration (a) as 1.6 m/s^2, we can calculate the net force using the formula F = m * a.

F = 72 kg * 1.6 m/s^2 = 115.2 N [forward]

b) Given the mass (m) of the model rocket as 2.3 kg and the acceleration (a) as 12 m/s^2, we can calculate the net force using the same formula.

F = 2.3 kg * 12 m/s^2 = 27.6 N [up]

c) Given the force (F) exerted by the cannon as 2.4 x 10^4 N [E] and the mass (m) of the shell as 5.0 kg, we can calculate the acceleration using the formula a = F / m.

a = (2.4 x 10^4 N) / (5.0 kg) = 4.8 x 10^3 m/s^2 [E]

d) Given the force (F) with which the hockey stick hits the puck as 24 N and the mass (m) of the puck as 160 g (0.16 kg), we can calculate the acceleration using the same formula.

a = (24 N) / (0.16 kg) = 150 m/s^2 [forward]

e) Given the net force (F) on the car as 1400 N [backwards], we can calculate the mass (m) using the formula F = m * a, where a is the acceleration. Rearranging the formula, we get m = F / a.

m = 1400 N / 1.2 m/s^2 = 1167 kg

f) Given the net force (F) exerted by the woman as 33 N [forward] and the acceleration (a) as 6.0 m/s^2 [forward], we can calculate the mass (m) using the same formula.

m = 33 N / 6.0 m/s^2 = 5.5 kg